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Transactions of the American 
Society of Civil Engineers 



American Society of Civil Engineers 



Sot Vf520.*:^8:-J 



\ 



%ci.iJi)cuuL,/m. 




ffearbarli College Ifbrarg 

FROM THE FUND OF 

CHARLES MINOT 

(OlMM of ISSS). 



SCIENCE CENTER LIBRARY 



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G 

f TRANSACTIONS 



AMERICAN SOCIETY . 



y</ 3 



CIVIL ENGINEEES 

(INSTITUTED 1852.) 



VOL. XI. 

JANUARY TO DECEMBER, 1882. 



NEW YORK : 



PUBLISHED BY THE SOCIETY. 
I 882. 



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;')'.^,.).383 




OFFICERS FOR THE YEAR ENDING DECEMBER 31, 1882. 

AsHBEi. Welch, President. 

James B. Eads, William H. Paine, Vice-PresUleufs. 

John Boqart, Seci'etary and Librarian. 

J. Jameb R. Cbobs, Treasurer. 

Joseph P. Davis, Thomas G. Keefeb, Thomab L. Casey, George S. Greene, Jr., 
George W. I>re88ER, Directors. 



Entered according to Act of OongresB, by The Amkbican Sogiktt of Civzl Evqutbxbb, in 
the Office of the Librarian of CongrcHS, iu Washington. 



N(yTE.— This Society is not responsible, as a body, for the (acts and opinions advanced 
in any of its publications. 



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CONTENTS. 



PAPERS. 



No. Month. Pao«. 

CCXXXn. ( January.) Experiment! Qpon PtaoBnix ColumnB. 

Presented June 16, 1881.— Clabxb, Rxsyxs kCo... 1 

COXXXm. {Feb.-March.) Diecnssloni upon Wrongbt-Iron €k>lamn0. Tests mnd For- 

mnlas 61 

By a. BousoAmcN 63 

By Thsodo&x CoopSB 66 

By D. J. Wbittkiiori 91 

By Gbarlbs B. Emsbt .*. 93-97 

ByDc VoLsoK Wood 95 

By G.L. Stbobxl 98 

By A. 8. C. WX7BTBLB 110 

By WiixzamH. Bubs Ill 

By IfAirsruLD Mbbbimam 116 

ByC.L. Oatbs 118 

By Jambs £. Howabd 119 

By Thomas 0. Olabkb 120 

COXXXIY. (AprU.) Aversging Machine. 

Bead March 1. 1882.— W. S. Auohimcloss 121 

COXXXY. (dd.) On the Bemoval of Incrustations in Water Mains ; a descrip- 

tion ot the operations performed in Halifax, N. 8., 
Canada. 

BeadMarch 1. 1882.— E. H. Kkatxmo 127 

CCXXXYI. {do.) On the Mode of Underpinning adopted for the Oroton Lake 

Bridge, N. T. C. & N. B. R., during the Bepalrs to the 
Masonry Piers 

Bead AprU 6. 1882.— A. P. BoLLBB 160 

COXXXYU. (May.) Annual Address. 

Read at the Convention of the Society, Washington, 

May 16. 1882.-nAshbbl Wxi/3H 168 

COXXXVIII. (June.) Sub- Aqueous Upderpinning. 

Read at the Annual CouTention, Msy 17, 1882.— A. G. 

Mknooal. 181 

CCXXXIX. (do.) The Mean Velocity of Stresms flowing in Natural Channels. 

Read February 16, 1882.— Robkbt E. McMatb 186 



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IV 



No. MOMTH. PaOE. 

CCXL, (July,) On ttie Detennlnition of the Flood Disohwge of BiTen And 

of the Back Wftter oftneed by Oontnotione. 

Betd December 21, 1882.— Willzaic B. Huttov .... 211 

(do.) DieciiMion on the Flood Dlioharge of BiTert: 

BjTbsodou O. Bujb 228 

ByBoBSXTE. MoMatb 282 

Bj William B. Hunov 284 

CCILI. (do,) Acooncy of MeMurement m IncreMed by Bepetitlon. 

Preeented at the Annual Oonvention. May 17, 1882. 

— Stkphkh S. Haxsht 242 

OOXLn. (Auguti.) The Orerflowof the Miatiaaippi Biver. 

Bead ICaroh 16, 1882.— Ltmah BuDoxa 261 

(do.) Diaonaaion on the OTorflow of the Misaiaaippi Biver : 

ByS. L. GoBTHBLL 268 

By J. A. OoKKBBOH 272 

By Ltkan BsiDOBa 274 

COXLin. (do.) Highway Bridgea. 

Preaented at the Annual Convention, May 19, 1882. 

— JamsbOwsh 277 

(do.) Diacnaaion on Bridgea : 

By AsBBBL Wklob 287 

OOXLIY. (StpUmbtr.) Uniformity in Bailway BoUing Btock. 

Bead June 21, 1882.— O. Ohakutb 201 

OOXLV. (do.) The Hndaon BiTor TnnneL 

Bead at the Annual Oonvention, May 19. 1882.— 

William Soot Bmith 814 

.;.... (do.) Diacuaaion on the Hudaon Biver Tunnel : 

By William H. Pains 823 

COXLYL (October.) Preaenration of Timber. 

Preliminary Beport of the €k>minitiee. Preaented 
at the Annual Oonvention, May 16, 1882.— O. 
CHAKrrs, Chairman 326 

(do.) Lettera aooompanying Beport on the Preaervation of Tim- 
ber: 

By JAMxa B. FBANOia 388 

ByJ.W. HoBABT 836 

By HuohBiddlx 886 

By M. ALXXi«DKB 886 

ByJ.W. PuTMAM 837 

ByM. G. HowB 842 

OOXLYn. (do.) The Kyan Prooeaa for Preaenration of Timber; ita uae and 
eifeot at Fort Ontario, N. Y., 1889 to 1882.— William P. 
JunaoM 346 



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No. 



OOXLYin. 



OOXLDL 



OCL. 



OOU. 



ooLn. 



V 

MoHTH. Page. 

{October.) Disonnloii on the Preseiration of Timb«r: 

BylfXHDM COBBI SSfr 

Bj A. OOTTUXB S66 

ByT. EoLEROM 866. 86S 

B7 Jamks B. Fkaxcxs 867 

B7 CLBMXirs HnwcHXL 86S 

BjEdwabdR. Ahdbkwv 860 

{November,) On the IncreMed EfBciency of BeilwaTi for the Tnniporta- 
tion of Freight. 

Bead December 20. 1882.~Wzllluc P. SHnm 866 

(do.) ' Bapid Method! in Topogntphioal Sorreying. 

Bead September 90, 1889.— William Bill Dawioii. 897 
{December,) DieenMlon on Bapid Methods in Topognphictl Sorrejlng: 

By Jamks P. Allxn 406 

{do.) Weights mnd Measures. 

Bead June 18, 1881.— Fbxdx. Bbooks. 406 

(do.) Diacnision on Weights and Measures: 

By Jacob M. Olabx 412 

{do.) On the Care and Maintenance of Iron Bridges. 

Bead October 18, 1882.— Hkhbt D. Bluitdbn 418 

{do.) Discussion on the Care and Maintenance of Bridges: 

ByTHKODOBB COOPKB 424 

{do.) A Pecnhar Phase of Metallic Behavior. 

Presented May 17, 1882.— O. E. MioBAZUs 429 

{do.) Discussion on a Peculiar Phase of Metallic Behavior: 

byT.EoLXSTON 432 

By O. B. MiOBABUS 486> 



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ILLUSTRATIONS. 



PLuVTK. Momth. 
{January.) 

(do.) 

{do.) 

{do.) 

{do.) 

{Ftb.-Mir.) 

(do.) 

{do.) 

{do.) 

{do.) 

{do.) 

{do.) 

{do.) 

{do.) 



Paper. 



Paos. 



/ I. 



{April.) 

{do.) 

{do.) 

{do.) 

m. {do.) 

lY. {do.) 



{do.) 



VL 


{June.) 


^ vn. 


{do.) 


vvm. 


{do.) 


^IX. 


{do.) 


\ X. 


{d4>.) 


VXI. 


{do.) 


xn. 


{do.) 



Diagram Illuiilratiiig Experiments upon Pboenix 

Ck)lumnfi CCXXXII. 2 

Cut niuBfg Specimen of Pbcenix Columns CCXXXH. 7 

do. do. Experiments upon Phcenix Columns OCXXXTI. 16 

do. do. do. do. do. do. CCXXXII. 53 

do. do. do. do. do. do. CCXXXH. 55 

Diagram niustratiug Discussion upon Wrought- 

IronColumns CCXXXHI. 64 

Cut Illustrating Discussion upon Wrought-Iron 

Columns CCXXXIH. 73 

Cut Illustrating Discussion iipou Wrought-Iron 

Columns CCXXXHI. 74 

Diagram Illustrating DiscusRion upon Wrought- 
Iron Columns CCXXXHI. 90 

Diagram Ulnstrating Discussion upon Wrought- 
Iron Columns CCXXXHI. 90 

Diagram ninstratlng Discussion upon Wrought- 
Iron Columns CCXXXHI. 94 

Cut niustrating- Discussion upon Wrought-Iron 

Columns CCXXXIH. 108 

Diagram Illustrating Discussion upon Wrought- 

IronCoIumns CCXXXHI. 112 

Diagram Illustrating Discussion upon Wrought- 
Iron Columns CCXXXIH. 118 

Cuts Illustrating the Averaging Machine CCXXXIV. 122 

do. do. do. do CCXXXIV. 123 

do. do. do. do CCXXXIV. 125 

do. do. Scraper for Water Mains. CCXXXV. 136 

Plan and Profile, Pipe Lines, City of Halifax CCXXXV. 140 

Illustration of Arrangement of Pipes, Valves, 
Hatch-Boxes and Mau-Holee, Halifikx Wat^r 

Works CCXXXV. 141 

Illustration of Mode of Underpinning adopted 
for Croton Lake Bridge during Bepairs to 

Masonry Piers CCXXXVL 152 

Quay Wall at Gosport Navy Yard OCXXXVm. 182 

Diagram of Discharge over Tremont Weir COXXXIX. 188 

Diagram fi-om Francis Lowell Experiments CCXXXIX. 194 

do. do. do. CCXXXIX. 196 

do. do. do. CCXXXIX. 198 

Diagram fkH)m EIUb' Connecticut Experiments.. . CCXXXIX. 200 

do. do. do. ... CCXXXIX. 202 



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VII 



Platk. 


MOKTH. 


•' TTTT 


(J-IIIW) 


^ XIV. 


(A>.) 


»- XV. 


(do.) 


•- XVI. 


(&>.) 


y xvn. 


(^i»/y.) 


^ xvm. 


(do.) 


i^XIX. 


(do.) 


^IX. 


(do.) 


^'XXI. 


{ii^:^ 


•" xxn. 


(do.) 


^Txrn. 


(do.) 


-XXTV. 


(do.) 


-XXV. 


(do.) 




K<^') 


^ XXVI. 


{A^guMl.) 


tocxvn. 


(do.) 


""^vm. 


(do.) 


^XXTX 


(do.) 


i^XXX. 


y^.) 




[SefUmhtr.) 


' XXXI. 


Kdo.) 


"•^Txxn. 


{do:S 


•^XXXTTT. 


{do.) 


•^xxxrv. 


{Dtctmbtr:^ 


' XXXV. 


(do. J 


(^ XXXVI. 


{^.) 


-^xxxvn. 


(do.) 


^xxxvnL 


(do.) 


»^ XXXIX. 


(do.) 


•^XL. 


(do.) 


^ XLI. 


(do.) 



Papeb. Paok. 

DiAKram from Columbus Ciauge of MifwiiiBippi . . CCXXXXX. *i04 

do. VickRburg do. .. COXXXIX. 206 

do. Carrolton do. .. CCXXXTX. 208 

Diagram of Gonditioua related to Mean Velocity. CCXXXIX. 210 

Map of Site of Oroasing of the New York. Lake 

Erie and Western Railroad by the New York, 

Lackawanna and Western Railway C(]XL. 216 

Cross Section of Preceding Map CCXL. 220 

Profiles of Water Surface CCXL. 224 

Plans and ProflleH CC^CL. 226 

Profiles of Water Surface CMJXL. 228 

PUn of StrecU in part of New York City CCXLI 244 

do. do. do. CCXLI. 246 

Repetition of Angular Measurements CCXLI. 248 

Calculated Positions of Monuments CCXLI. 248 

Cut Illustrating Accuracy of Measurement as 

increased by Repetition CCXU. 2fiO 

Map of Portion of the Mississippi Delta OOXUI.- 264 

Approximate Section of the Mississippi River at 

Carrolton CCXTiTT. 266 

Illustrations of Highway Bridges CCXUII. 282 

do. do. OCXLin. 284 

do. do. CCXUn. 286 

Cuts of Grip Bolt and Spiral Wedge Nut CCXLIV. 311 

Hudson River Tunnel, Jersey Side CCXLV. 318 

Hudson River Tunnel with relation to the Bulk- 
head Wall in New York City CCXLV. 320 

Hudson River Tunnel, New York Caisson CCXLV. 322 

niustration showipg Value of Merchandise Im- 
ported into the United States, subdivided by 

Countries where produced or grown OCL. 412 

Illustration of a Peculiar Phase of Metallic 

Behavior CCUI. 430 

Illustration of a Peculiar Phase of Metallic 

Behavior CCJLH. 480 

Illustration of a Peculiar Phase of Metallic 

Behavior CCUI. 430 

Illustration of a Peculiar Phase of Metallic 

Behavior COUL 430 

niustration of a Peculiar Phase of Metallic 

Behavior CCUI. 432 

Illustration of a Peculiar Phase of Metallic 

Behavior OCUL 432 

Illustration of a Peculiar Phase of Metallic 

Behavior CCLH. 432 



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ERRATA. 

Page 76 : the pltu Bign in the denomiuatorfl of the formulie (a), (b), (e) and (d) should 
be -f 

Page 90 : make the same correction as al>ove in formulfp on Diagram No. 2. 
Page 90 : add another cipher to the numerators of formulae on Diagram No. 2. 

The text should have explained that the point of reversion of the curves on Diagram 
No. 2 being assumed at 80 radii of gyration for (a), (6) and (c), at 33 radii of gyration for {d), 
the i>(itf sign should only be used for values of B greater than these numbers ; for values of 
B less than these numbers, the mituu sign should bo used. 

Formuln (6) to (14) being derived Arom the above formula^, will, of course, be subject to 
the same explanation. 



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AMEMOAN SOOIETT OF CIVIL ENGINEEES. 

INSTITUTED 1852. 



TRANSACTIONS. 

NoTK. — ThiB Society is not responsible as a bodj, for the fScuits and opinions adranoed in 
any. of its pnblibations. 



CCXXXII. 

(Vol. XI.— January. 1882.) 



EXPERIMENTS UPON PHCENIX COLUMNS. 



Presented at the 13th Annuaii Convention, June 15th, 1881, by 

T. 0. Clabkb, a. Bonzano, John Qripfen and David Reeves, 

(Olabke, Beeves & Co.) Members A. S. C. E. 

WITH DISCUSSION. 



The undersigned submit, for the information of the Society, certain 
experiments npon the breakiAg strength, elastic limit, etc., of fnll sized 
Phoenix colomns, snch as are nsed in bridges, made npon the U. S. 
€h)vemment testing machine at Watertown (Mass.) Arsenal, at their 
request and cost. 



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2 



These experiments are given in great detail, and are accompanied by 
a carefully written description of the testing machine, and of the manner 
in which the tests were made, by James E. Howard, C. E., the official in 
charge of testing machine. 

These results show that Gordon's formula does not express the true 
strength of these columns ; and it would appear that separate formulae 
would have to be used for long and for short columns below 15 diameters, 
a result indicated by Hodgkinson. (See Treatise on Cast Iron, p. 337.) 

The Phoenix columns are stronger than Gordon's formula indicates, 
as the following diagram, showing the curves of ultimate strength, both 
by the Watertown experiments and as calculated by Gordon's formula, 
clearly shows. 



AOOOO 




OIArv«ETERw5 \M LE^lCT-^ 



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The whole is submitted in the hope that it will throw additional 
light upon an important engineering question, and aid in further study 
of this subject. 

CLARKE, REEVES & CO. 

May, 1881. 



Description of Machine and Experiments. 
By James E. Howard, C. E. 

The XJ. S. Government testing machine is an hydraulic, horizontal 
testing machine. It has a capacity of 800 000 pounds for strains of 
tension or compression, and capable of receiving specimens of any length 
up to 30 feet, and by a slight modification of the parts can be adapted 
for compression tests 31 feet 11 inches in length, and for tensile tests of 
eye -bars 37 feet 3 inches centre to centre of eyes. 

The principal parts of the machine are the platforms of an hydraulic 
scale at one end, a straining press at the other end, and connectiDg them 
two main screws of wrought iron S\ inches diameter, 48 feet long. 
Specimens are placed between the straining press and the scale plat- 
forms, central with the screws. The press has a cylinder 20 inches 
diameter by 24-inch stroke ; it is carried upon a truck and moved from 
or towards the opposite end, to accommodate specimens of different 
lengths, by nuts working on the main screws, the nuts being driven 
by a central shaft. These parts, which are subject to the greatest strains 
while testing, are fixed or stationary as regards their relative position 
only. They may take a slight longitudinal movement in whichever 
direction the shock of recoil predominates. The movement is gradually 
checked by a buffing apparatus. Hydraulic power for moving the piston 
of the straining press is supplied from an accumulator. This consists of 
a vertical cylinder, having a 10-inch ram which in turn is bored and 
forms the cylinder for a 7^-inch ram. Upon these rams, which are 
used independently, are carried one, two or three masonry weights, 
varying the cyhnder pressure from 780 pounds per square inch to 3 500 
pounds per square inch. The ram which is put into use, and the num- 
ber of weights carried, depends upon the strength of the specimen under 



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test. A steam-pump raises the weights. The use of the accumulator 
allows of rapid manipulation of the machine ; those pulsations incidental 
to pumping directly into the straining press cylinder are avoided. 

The apparatus for weighing the strains applied to the specimen are in 
duplicate. The hydraulic scale measures the loads from one end of the 
specimen ; pressure gauges connected with the straining press indicate 
the load from that end. 

The veracity of the pressure gauges is impaired by packing- friction, 
to reduce which an apparatus was designed for rotating the press piston 
by a force independent of that which caused stress in the specimen. 
With this apparatus it would make a very excellent testing machine if 
used without the hydraulic scale ; but the latter, being entirely free from 
friction, admits of much closer weighing. 

The use of the rotary apparatus complicates the manipulation of the 
machine, and not being required, owing to the superior behavior of the 
scale, it is set aside and not used. The pressure gauges in connection 
with the machine are specially worthy of remark. They are diaphragm 
gauges, have 20 inch dial, and from 1000 lbs. per square inch to 3500 lbs. 
per square inch capacity. The usual difficulties in the construction of 
gauges have, with these, been entirely surmounted. The vagaries of 
ordinary gauges are rendered apparent by comparing the ascending and 
descending readings under the same loads. 

High pressure gauges are proportionally less accurate than those of 
low pressure. 

The testing-machine gauges are correct almost to mathematical exact- 
ness. 

The hydraulic scale platforms receive directly the specimen loads, 
and transmit the same to the weighing beam without loss by friction ; 
the net load is here indicated. The superiority of this machine is in a 
large part due to the accuracy of the scale. It has been tested in the 
most severe manner, and proved satisfactory. From the fracture of a 5 
inch bar of wrought-iron, requiring over 700,000 lbs. tension, the change 
was immediately made to a specimen which broke with one pound ten- 
sion, the scale correctly indicating the load in each case . 

During the preliminary work upon the testing-machine adjustments, 
it is believed some of the most remarkable weighing was done that has 
yet been accomplished, when the mass of metal weighed is considered. 
The main weighing beam was temporarily arranged as an even balance 



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flcale, and standard weights adjusted npon it. Two 200 lb. weights 
were adjusted to lo oJo ooo ot their weight. "With weights of this size 
in the poise pans, the scale was sensitive to fS of a grain in change of 
load. 

This series of tests embrace twenty Phoenix columns of 8.04 inches 
diameter, 4 segments, in duplicate lengths running from 8 inches to 28 
feet long. The sectional area of the metal being slightly in excess of 12 
square inches. Also the test of two columns of six segments 11.8 inches 
diameter ; sectional area, 18.3 square inches and 8 feet 9^ inches, and 25 
feet 2.65 inches in length respectively. 

The sectional area was computed from the weight of the columns; 
careful measurements and the specific gravity gave the weight of the iron 
.27556 lbs. per cubic inch. 

All were tested with flat ends. Care was taken that the strains of 
compressions while under test should pass exactly through the axis of the 
columns. The ends resting between the planed faces of compression 
platforms in the testing machine were brought to a good bearing. 

Short columns were unsupported between the ends ; those from 10 
feet to 19 feet in length were supported at the middle ; those above 19 
feet long had two intermediate supports. For this purpose weights 
counterbalancing their proper length of column were attached to one 
end of a rope, which rope was passed over an overhead pulley, and had 
its other end secured to the column. This method secures the columns 
from any tendency to deflect downward from their own weight, while 
allowing full movement in whichever direction crippling takes place. 

The method adopted in conducting the tests, the columns being 
properly in position, was to apply an initial load of 10 000 lbs. or 20 000 
lbs., according to the weight of the column, gradually apply the higher 
loads, and measure the amount of contraction at each successive loading. 
Between each increment of load, strains were released to the initial pres- 
sure, and the permanent set of the metal measured. Measurements were 
taken with vernier calipers, reading to the one-thousandth of an inch, 
between the ends of rods laid along the columns, reaching to the com- 
pression platforms at either end. Vertical and horizontal deflections 
were measured at the middle of the columns. 

Loads were increased till the ultimate crippling strength was deter- 
mined. In a number of cases strains were continued until the columns 
were considerably bent, even to one diameter out of line, and the loads 



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6 

they would sustain in that condition measured. The elastic limit with 
some columns was ascertained with difficulty. The earliest loads devel- 
oped a slight permanent set, which increased as higher strains were 
reached. This behavior of the metal was attributed, in a certain degree, 
to the condition of the ends of the columns, the flanges of some being 
shorter than the web ; in others the ends were not squared off smoothly. 
When doubts existed as to where the elastic limit was, it is not given in 
the results. Loads very much above the elastic limit produce an imme- 
diate shortening, but not all the metal would yield to if the loads were 
long sustained. Observing a 4: feet column, No. 17, to ascertain the rate 
of decrease in length after the flrst yielding under that strain had taken 
place, it was found that sustaining 430 000 lbs. = 35 590 lbs. per square 
inch for 40 minutes, caused a further decrease in length of .018 inches. 

This decrease in length took place in the following time: 
After sustaining 35 590 lbs. persq. inch, 5 minutes, decrease of .004 inch. 



10 
20 
30 
40 



.009 
.013 
.016 
.018 



The extent, therefore, the columns were compressed under loads above 
the elastic limit furnishes comparative, rather than absolute results, the 
time between loadings having been kept the same as nearly as possible. 

The ultimate crippling strength was determined with moderation. 
By hurrying a test at this point, without allowing the metal sufficient 
time in which to act, a column could be made apparently to sustain a 
higher load than in reality was possible. The behavior of the columns, 
after taking a deflection of several inches, was remarkable. As the de- 
tails of the tests will show, they still retained a superior sustaining 
power, and herein they differ materially from lattice columns. The 
latter form, after deflecting slightly, suddenly give way by tearing out 
the riveting of the lattice bars, after which but little strength, as a 
column, remains. 



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7 

Watertown Absbnaij, Mass. Novbmbeb, 1879. 

test of oompbession op 

TWENTY PHGENIX COLUMNS. 

Form of Specimens and Approximate Dimensions. 




Diameter ont to out of flanges 11 .5 inches. 

** centre to centre of rivets 10 . " 

Columns tested in a horizontal position. 

Those under 10 feet in length supported at ends only. 

Those 10 feet and under 19 feet supported at ends and counter 
weighted at middle. 

Those 19 feet and over in length, counter weighted at one-third 
distance from each end. 

Flat ends of columns brought to good bearings, adjusting compres- 
sion platforms, a few thousandths of an inch, when rendered neces- 
sary by the columns not having ends truly parallel. 

Graugings were taken showing the total compression and the deflec- 
tions horizontally and vertically at the middle of the column. 

The columns were positioned with flanges, as shown by the above 
sketch. 

The sectional area was computed from the weights of the columns ; 
the weight per cubic inch .27556 pounds, found by careful measure- 
ment of a 25 feet column and verified by specific gravity of pieces out 
out of one of the specimens. 

It is somewhat difficult to determine in every case the limit of 
elasticity ; the columns under light loads showing some permanent 
set as though they were taking a better bearing or releasing some initial 
strains in the metal. However, this permanent shortening seems rather 
insignificant, amounting to a few thousandths in the longest column. 



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9 
DETAILED STATEMENTS OF TESTS. 

STATEMENT No. 1. 

Length of oolTunn 28 feet 

Sectional area 12.062 square inches. 

Weight 1 142 pounds. 

Initial load on specimen 20 000 pounds. 

Loads on specimen applied and permanent set measured when load 
removed to initial strain. 



LOAXM ToUl Per Horiz. Vert. !>•„*„». 

Appuxo. Oomp. Set. Defleo. Defleo. kemabm. 

Lbs. Inches Inches Inches Inches 
20000 

200 000 .190 002 .029 

20000 006 

240 000 

20 000 008 

252 000 

20000 008 

264 000 

20 000 010 

270 000 

20 000 010 

276 000 

20 000 Oil 

282 000 

20 000 Olli 

288 000 

20 000 011^ 

294 000 

20 000 012 



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10 

Statement No. 1— -Continued, 



Loads Total Per Horlz. Vert. „ 

Applied. Comp. Set. Defleo Deflec RBMABKg. 



Lbs . Inches Inches Inches Inches 
300 000 

20 000 012 

306 000 

20 000 013 

312 000 

20 000 OU-f 

318 000 

20 000 016 

324 000 

20 000 018 

330 000 

20 000 018-f 

336 000 

20 000 019 

342 000 

20 000 020A 

348 000 

20 000 022J 

354 000 

20 000 023i 

360 000 .368 

20 000 025i 

366 000 

20 000 027 



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11 

Statement No. 1 — Continued. 



Load* Total Per Horlz. Vert Ri 

Applied. Comp. Set. Defleo. Defleo. 

Lbs. Inohes Inches Inches Inches 
372 000 

20000 030 

378 000 

20 000 031 

384000 

20 000 034 

390 000 

20 000 036 

396 000 .418 086 .137 

20 000 041 

402 000 

20 000 044 

424 000 Ultimate strength, 35 150 pounds 

t per square inch. 

20 000 2.73 1.80 

282 000 Load sustained after deflection as 

above. 
20 000 4.56 3.30 

216 000 Load sustained after deflection as 

above. 

Columns deflected east and downward. 



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12 

STATEMENT No. 2. 

Length of specimen 28 feet 

Sectional area 12 181 square inches. 

Weight 1 163 pounds. 

Initial load on Specimen 20 000 pounds. 



Loads Total Per Ho«. Vert. 
Applikd. Oomp. Bet Deflec. Defleo. 



Lbs. Inches Inches Inches Inches 
20 000 

200 000 .186 014 .046 

20000 006 

240 000 

20 000 006 

262 000 

20 000 006 

264 000 

20 000 007 

270 000 

20 000 007t 

276 000 

20 000 007i 

282 000 

20 000 007i 

288 000 

20 000 009 

294 000 

20 000 010 

300 000 

20 000 010 



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13 

Statembnt No. 2— Continued, 



Loads ToUl Per Boris. Vert. Rucabxi. 

▲ppuxd. Comp. Set Defleo. Dafleo. 



Lbs. Inches Inches Inches Inches 
306 000 

20 000 010 

312 000 

20 000 Om 

318 000 

20 000 013 

324 000 

20 000 013 

330 000 

20 000 015 

336 000 

20 000 017 

342 000 

20 000 019 

348 000 

20 000 020 

354 000 

20 000 021 

360 000 

20 000 024 

366 000 

20 000 026 

372 000 

20 000 027 



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14 

Statement No. 2 — ContinuecL 



Loads Total Per Horlz. Yert. 
Appuxd. Oomp. Set. Deflec. Defleo. 



R] 



Lbs. Inches Inches Inches Inches 
378 000 

20 000 031 

384 000 

20 000 032 

390 000 

20 000 035 

396 000 

20 000 039 

402 000 .424 

20 000 046 

416 000 Ultimate strength, 34 160 pounds 

per square inch. 

20 000 05 2.48 

306 000 Sustained after above deflection. 

20 000 3.98 

263 000 Sustained after above deflection. 

250 000 5.34: 



. 134 Elastic reaction. 
20 000 4. 



L34| 



Columns deflected upwards. 



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15 

STATEMENT No. 3. 



Length of colnmu 25 feet. 

Sectional area 12.233 square indues . .weight, 1 034 pounds. 
Placed in machine with hemispherical ends. 






Paper wrapped around stems of hemispherical ends to bring size up 
to interior diameter of the column, and properly centre them. 

The ends were found, however, not to be perfect hemisphere at south 
end of column bearing about one-half inch above centre. 




Loads ToUl 
Appukd. Comp- 



Per 
Set 



Horiz. Vertical 
Deflec. . Deflec. 



REMABK8. 



Lbs. Inches Liches Inches Inches 
20 000 



50 000 

20 000. 
100 000 

20 000. 
150 000 

20 000, 
200 000 

20 000 



.033 009 .086 Deflecting downwards. 

.006 

.089 016 .151 

010 

.141 008 .178 

012 037 

.197 03 .324 

015 



250 000 .262 09 .651 

20 000 '. . .024 .024 .102 South hemisphere turned one-half 

20 000 
200 000 03 



over for the purpose of taking 
out permanent deflection .102 
inch, end now bearing one-half 
inch below centre line of column. 



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»• ^H!?'' 



16 



Statement No. S—OtmtiftuecL 



Loads Total Per Horlz. Y«rt. Rkmabm 

Applied. Oomp. Set. Deflec. Deflect 

Lbs. Inches Inches Inches Inches 
250 000....; 113 

20 000 03 

275 000 .241 254 

20 000 79 

290 000 

20 000 11 Per deflection removed as taken and 

set in opposite direction (.110—- 
.102=. 008) 



Hemispherical ends removed and column tested with flat ends, same 
as all others were tested. 



Loads nr»™r» ^«r Horia. Vertical 
Appukd. ^™P* Set. Deflec. Deflec. 

Lbs. Inches Inches Inches Inches 
20 000 

300 000 .255 016 .017 

20 000 009 

306 000 

20 000 009 

312 000 

20 000 009 

318 000 

20000 009 

330 000 

20 000 009 



Remarks. 



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17 
Statement No. S— Continued. 



Loads Total Per Horiz. Vert. Rkmarm 

Applied. Comp. Set. Defleo. Deflec. 



Lbs. Inches Inches Inches Inches 

342 000 Elastic limit, 27 960 pounds, square 

inch. 
20 000 009 

354 000 

20 000...... .013 00 

396 000 .356 014 .114 

20 000 029 044 

431 500 Ultimate strength, 35 270 pounds, 

square inch. 
20 000 709 

382 000 Sustained after deflection as above. 

20 000 1.838 

346 000 «« «< «« «< «« 

20 000 3.676* 

292 000 M »« «« ♦< *€ 

20 000 4.357 

274 000 ♦* ** ** " ** 

20 000 6.102 

218 000 8.732 

20 000 6.695 



2.037 Elastic reaction. 



The ends of the above column did not come to as good bearing, 
when test began, as usual with other columns. 



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18 
STATEMENT No. 4. 

Length of column 25 feet. • 

Sectional area 12 . 10 square inches. 

Weight 1 023 pounds. 



Loads r^imn P®^ Horiz. Vertical 

AppLiKD. ^o™P- Set. Deflec. Deflec. 



Lbs. Inches Inches Inches. Inches. 
20 000 

200 000 .168 015 .084 

20 000 (X)7 .005 .024 

240 000 .205 022 .091 

20 000 Oil 

252 000 
264 000 

20 000 012 

276 000 

20 000 012 

288 000 

20 000 014 

300 000 .264 041 .099 

20 000 016 .005 .0^2 

312 000 

20 000 018 

324 000 

20 000 020 

336 000 

20 000 022 

348 000 



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19 

Statement No. 4 — Continued 



LOAiM*. ^ Per Horiz. Vertical. Remarks. 



Lbs. Inches Inches Inches. Inches. 

20 000 025 .024 .051 

396 000 .377 149 .127 

20 000 047 .077 .067 

424 000 Ultimate strength, 35 

040 lbs . square inch. 
20 000 1.715 .244 

348 000 Sustained after above de- 
flection. 
20 000 4.055 .486 

280 000 Sustained after above de- 
flection. 
250 000 6.285) .896] 



20 000. 



6.285) .896) 

V 1 . 35 y . 25 in. Elastic reaction . 

4.935) .646) 



251 000 Sustained after above de- 
flection. 

170 000 9,71 

-2.3 ^.4 

20000 7.4| 



1.2) 



178 000 10.3 1.7 Sustained after above de- 

flection. 



Column deflected east and upward. 



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20 

STATEMENT No. 5. 

Length of column 22 feet. 

Sectional area 12 371 square inches. 

"height 920 pounds. 



Loads ^ Per Horiz. Vertical 

Afpliid. ^«™P- Set. Deflec. Deflec. Rkmabm. 



Lbs. Inches Inches Inches Inches 
10 000 

50 000 .037 036 .011 

10 000 001 

100 000 .078 042 .013 

10 000 002 

150 000 .121 046 .016 

10 000 003 

200 000 .160 050 .014 

10 000 004 

250000 .201 054 .016 

10 000 008 

260 000 .209 

10 000 008 

270 000 .218 

10 000 009 

280 000 .227 

10 000 010 

290 000 .234 

10 000 010 

300 000 .243 059 .021 

10 000 012 

305 000 .248 • 



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21 

Statement No. 5~ Confirmed. 



^^^^ Como ^^^ ^°''**- Vertical Rbmabkb 

APPIJEO. ^™P- Set. Deflca Deflec. kkmabkb. 



libs. Inches Inches Inches Inches 

10 000 013 

310 000 .253 

10 000 014 

315 000 .257 

10 000 015 

320 000 .262 

10 000 016 

325 000 .267 

10 000 018 

330 000 .272 

10 000 018 

335 000 

10 000 020 

340 000 

10 000 021 

345 000 

10 000 022 

850 000 .293 065 016 

10000 023 

355 000 

10 000 024 

360 000 

10 000 025 

365 000 



Digitized by 



Google 



22 
Statement No. 5 — Continued, 



Loads ^ Per Horlx. Vertical Bemabkb. 

Applied. '-^*"*'' Set Defleo. Deflec 



Lbs. Inches Inches Inches Inches 
10 000 029 

370 000 

10 000 081 

375 000 

10 000 031 

380 000 

10 000 033 

385 000 

10 000 036 

390 000 

10 000 038 

395 000 

10 000 041 

400 000 3,51 .072 .012 

10 000 045 

410 000 

10 000 049 

420 000 

10 000 058 

430 000 

10 000 070 



440 000 Ultimate strength, 35 570 pounds, 

square inch. 



Column deflects, downward and east. 
Maximum deflection about one foot from middle. 
Flanges open about .01 inch between rivets concave side. 
Notwithstanding the large number of measurements taken of above 
column it is somewhat problematical what the Elastic Limit is. 



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23 



STATEMENT No. 6. 

Length of colnmn 22 feet. 

Sectional area 12.311 square inches. 



Loads r»««,« ^^ Horlz. Vert. 
Afpuxd. ^<»™P- Set Deflec. Deflec 



Libs. Inches Inches Inches Inches 
10 000 



50 000 .054 

10 000 

100 000 .072 

10 000 

150 000 .113 

10 000 . . . 
200 000 .152 

10 000 . . . 
240 000 .185 

10 000 

260 000 .201 

10 000 

270 000 .210 

10 000 . . . 
280 000 .219 

10 000 

290 000 .227 

10 000 

300 000 .236. 

10 000... 
310 000 .244 

10 000 012 



001 
002 
003 
004 
006 
006 
008 
009 
010 
Oil 



.014 .048 



.018 .073 



.023 .109 



.025 .121 



.028 .131 



Bexabks. 



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24 

Statement No. &~ Continued. 



^*^* Pnmn ^®^ Horlz. Vert Rkmabkb 

APPUKD. ^^™P* Set. Deflec Doflec. Kemabkb. 



Lbs. iDoLes Inches iDches luches 
320 000 .254 

10 000 015 

330 000 .263 

10 000 016 

340 000 .274 

10 000 019 

350 000 .283 030 .157 

10 000 019 

360 000 .293 

10 000 022 

370 000 .304 

10 000 024 

380 000 .315 

10 000 028 

890 000 .327 

10 000 034 

400 000 .340 032 .215 

10 000 .038 
423 000 Ultimate strength, 34 360 lbs. sq.in. 

10 000 2. 
357 600 Load sustained after above deflec. 

10 000 

300 300 3.95 Columns cease to bear on full face 

of ends. 



Digitized by VjOOQ IC 



25 



Statement No. 6 — Continued. 



Loads nrt«,« ^•'f Horiz. Vert. rcmarks 

Appukd. ^""P- Set. Deflec. Deflec. Remabkb. 

Lbs. Inches Inches Inches Inches 

10 000 4. 

300 900 Sustains after above deflection. 

10 000 6. 
261 000 *' '* ** 

10 000 8. 

214 000 Sustains after above deflection, 

ends bearing about i way round. 
10 000 1.8 inch vertical reaction. 

Column deflected upward. 

STATEMENT No. 7. 

Length of column 19 feet. 

Sectional area 12.023 square inches, 

Weight 773 pounds. 



Loads n-,„„ Per Horiz. Vert. 
Applied. ^°™P- set. Deflec. Deflec. 

Lbs. Inches Inches Inches Inches 
10 000 

240 000 .163 075 .024 

10 000 001 

262 000 

10 000 001 

264 000 

10 000 001 

276 000 

10 000 001 



Rbmabrb. 



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26 
Statement No. 1— Continued, 



Loads n/%««« P®' Horix. Vert. r»mai»w« 

Applied. ^^°^P- Set Defleo. Deflec Bemaiuw. 



Lbs. Inches Inches Inches Inches 
288 000 



10 000 003 

300 000 .198 092 .024 

10 000 005 

312 000 

10 000 005 

324 000 

10 000 008 

336 000 

10 000 010 

348 000 

10 000 012 

360 000 

10 000 015 

372 000 

10 000 018 

396 000 

10 000 027 .069 .002 

425 200 Ultimate strength, 35365 lbs. sq.in. 

10 000 123 .682 .02 

412 000 Sustained after above deflection. 

10 000 3.64 .112 

318 000 ** ** ** 

10 000 6.19 .37 



Digitized by VjOOQ IC 



27 

Statement No. 7 — Continued, 



Loads r«A«i« ^^^ Horia. Vert. RKiciLRKfl 

Applied. ^°^P- Bet. Deflec. Deflec bemams. 

Lbs. Inches Inches Inches Inches 
252 000 Sustained after above deflection. 

10 000 10.53 .83 

157 000 



Column deflected to the east and upward. 



STATEMENT No. 8. 



Length of column 19 feet. 

Sectional area 12.087 square inches. 

Weight 777 pounds. 



Applied. C°™P- Set. Deflec. Deflea 



Lbs. Inches Inches Inches Inches 
10 000 

200 000 .139 006 .027 

10 000 005 

240 000 .168 008 .030 

10 000 007 

252 000 

10 000 007 

264 000 

10 000 007 

276 000 

10 000 007 

282 000 



Digitized by VjOOQIC 



28 
Statement No. 8 — Continited. 



Loads ^ Per Horiz. Vert. Rrmabks. 

APPLIED. ^°°*P- Set Defleo. Deflec. wkmaiui^b. 



Lbs . Inches Inches Inches Inches 
10 000 009 

288 000 

10 000 009 

294 000 

10 000 009 

300 000 .213 016 .032 

10 000 010 

306 000 

10 000 010 

312 000 

10 000 013 

318 000 

10 000 013 

324 000 

10 000 013 

330 000 

10 000 013 

336 000 

10 000 016 

342000 

10 000 016 

348 000 

10 000 016 

354 000 Elastic limit, 29 290 lbs. sq. in. 



Digitized by VjOOQ IC 



29 

Statement No. S— Continued. 



^^*^' Comn ^®' Horlz. Vert. ti»mai.w« 

Appued ^*^™P- Set. Deflea Deflec. Bkmarm. 



Lbs. Inches Inches Inches Inches 
10 000 016 

360 000 

10 000 017 

366 000 

10 000...... .019 

372 000 

10 000 022 

378 000 

10 000 025 

384 000 

10 000 025 

390 000 

10 000 027 

396 000 

10 000 030 

446 000 Ultimate strength, 36 900 lbs. sq.in. 

10 000 60 .14 

415 000 Load sustained after above deflec- 
tion. 
10 000 1.77 .18 



364 000 «* " " 

10 000 2.38 

10 000 2 .48 Maximnm deflection one foot from 

mAle. 
350 000 3.22 Sustwned after above deflection. 

10 000 2.73 

Ck)lamn deflected west and upward. 



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80 

STATEMENT No. 9. 

Length of column 16 feet. 

Sectional area 12.000 square inches. 

Weight 650 pounds. 



^*^s romn ^®' Horiz. Vert Bemams 

Appued. ^®™P- Set. Defleo. Deileo. kemabks. 



Lbs. Inches Inches Inches Inches 
10 000 

200 000 .120 022 .002 

10 000 006 

240 000 

10 000 007 

252 000 

10 000 007 

264 000 

10 000 009 

270 000 

10 000 010 

276 000 

10 000 010 

282 000 

10 000 Oil 

288 000 

10 000 Oil 

294 000 

10 000 012 

300 000 • 

10 000 012 

306 000 



Digitized by VjOOQ IC 



31 

Statement No. 9 — Continued, 



^^*^ Comn ^®' Horlz. Vert. Rkmabkb 

Applifd. ^™P- Set. Defleo Deflec. Bkmabks. 



Lbs. Inches Inches Inches Inches 
10 000 013 

312 000 

10 000 013 

318 000 

10 000 015 

324 000 

10 000 016 

330000 

10 000 017 

336 000 

10 000 018 , 

348000 

10 000 020 

360 000 

10 000 023 

372 000 

10 000 026 

396 000 

10 000 034 

439 000 Ultimate strength, 36 5801bs.sq.in. 

10 000 2 .09 Maximum deflection one foot from 

middle. 
365 000 Sustained after above deflection. 

Column deflected eastward. 



Digitized by VjOOQIC 



32 

STATEMENT No. 10. 

Length of column 16 feet. 

Sectional area 12.000 square inches. 

Weight 660 lbs. 



Loads n««^.^ P®""- Horlz. Vertical ^ 

APPLIED. ^°™P' Set. Deflec. Deflec. Rkmarms. 



Lbs. Liches Inches Liches Inches 
10 000 

200 000 .116 013 .012 

10 000 003 

240 000 

10 000 004 

262 000 

10 000 004 • 

264 000 

10 000 006 

270 000 

10 000 005 

276 000 

10 000 006 

282 000 

10 000 006 

288 000 

10 000 008 

294 000 

10 000 008 

300 000 

10 000 008* 

306 000 



Digitized by VjOOQIC 



33 

Statement No. 10 — Continued. 



Loads 
Applibd. 


Comp. 


Per Horiz. Vertical 
Set. Deflec. Deflec. 


Bkmabke. 


Lbs. Inches Inches Inches Inches 


I 


10 000 . 




.009 






312 000 






10 000 . 




.010 






318 000 






10 000 , 




.011 






324 000 






10 000 . 




.012 




. 


336 000 










10 000 . 




.013 






348 000 




• 


10 000 . 




.015 






360 000 . 






10 000 . 




.018 






372 000 










10 000. 




.021 






396 000 










10 000. 




.028 






439 000 . 








Ultimate strength, 36 580 lbs. 


10 000 . 




3.22 




square inch. 


342 000 . 






Sustained after above deflection. 


10 000 . 




4.93 






305 000. 




5.92 


(( << (( 


10 000 . 




5.34 
















.58 


Elasticity. 



Column deflected towards the east. 



Digitized by VjOOQ IC 



34 

STATEMENT No. 11. 

Length of column 13 feet. 

Sectional area 12.185 square inchep.. 

Weight 536 lbs. 



^*^* <^omn P®^- Horlz. Vertical 
APPLIED, ^omp. g^^ Deflec. Deflec. 



Lbs. Inches Inches Inches In ches 
10 000 

200 000 .092 013 .045 

10 000 005 

240 000 

10 000 005 

252 000 

10 000 005 . 

264 000 

10 000 007 

270 000 

10 000 007 

276 000 

10 000 007 

282 000 

10 000 008 

288 000 

10 000 008 

294 000 

10 000 008 

300 000 .142 017 .048 

10 000 009i 

306 000 



Digitized by VjOOQ IC 



35 

Statement No. 11 — Continued. 



Applied; ^^'"v- get Deflec Defleo. 

Lbs. Inckes Inches Inches Inches 

10 000 009i 

312 000 

10 000 010 

318 000 

10 000 010 

324 000 

10 000 Oil 

330 000 

10 000 Oil 

336 000 

10 000 012 

342 000 Elastic limit, 28 890 lbs. sq. in. 

10 000 012 

348 000 

10 000 014 

354 000 

10 000 015 

360 000 

10 000 015i 

366 000 

10 000 016 

372 000 

10 000 017 



Digitized by VjOOQ IC 



36 

Statement No. 11 — Continued, 



^^^" romn P®"" HoHz. Vertical 
Applied. ^°™P- Set. Deflec. Defleo. B«ma»m. 

Lbs. Inches Inches Inches Inches 
384000 

10 000 019 

896 000 

10 000 022 

^9 <^ Ultimate strength, 36 857 lbs. 

, ^ ««^ square inch. 

10 000 1.44 .234 

406 000 Sustained after above deflection. 

10 000 3.88 *45 

365 000 ' «« «« 

10 000 6.40 .48 

268 000 «* ** ** 



Column deflected to the east. 

STATEMENT No. 12. 

Length of Column 13 feet. 

Sectional area 12.069 square inches. 

Weight 531 pounds. 



Loads ^ Per Horiz. Verttcal Kemaem. 

ApPLiitD. ^""*F» 8e Deflec. Deflez. *»«.-j.jm«. 



Lbs. Inches Inches Inches Inches 

10 000 

200 000 .091 018 .029 

10 000 004 

240 000 

10 000 006 



Digitized by VjOOQ IC 



37 

Statement No. 12 — Continued, 



Applibd. ^™p- Set Defleo. Defleo. »*-a«»ii 



Lbs. Inches Inches Inches Inches 
252 000 

10 000 007 

264 000 

10 000 007 

270 000. 

10 000 008 

276 000 

10 000 008 

282 000 

10 000 008 

288 000 

10 000 008 

294 000 

10 000 010 

300 000 

10 000 Oil 

306000 

10 000 Oil 

31!i 000 

10 000 012 

318 000 

10 000 012 

324 000 

10 000 013 



Digitized by VjOOQIC 



38 
Statement No. 12 — Continued. 



Loads ^ Per Horiz. Vwtical Bemarks. 

Applied. ^"*"P- set Defleo. Defleo. »»i»^«.o. 



Lbs . Inches Inches Inches Inches 
330 000 

10 000 014 

336 000 

10 000 om 

342 000 

10 000 015 

348 000 

10 000 om 

354 000 

10 000 019 

360 000 

10 000 020 

366 000 

10 000 022 

372 000 

10 000 025 

384 000 

10 000 030 

396 000 

10 000 034 

449 000 Ultimate 8trength,37 200 lbs. sq. in. 

10 000 2.2 .34 

390 000 Sustained after above deflection. 

10 000 3.85 .61 



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39 
Statement No. 12 — Continued, 



Loads ^ Per Horlz. VerticiU Rbmabks. 

Applied, ^""'i'- set. Defleo. Defleo. 



Lbs . Inches Inches Inches Inches 
362 000 Sustained after above deflection. 

10 000 5.51 1.45 

284 000.; ** *• ** ** 



Column deflected to the west and upward. 

The permanent set of this column was probably mostly confined to 
one end ; which had flanges short. 

STATEMENT No. 13. 

Length of Column 10 feet. 

Sectional area ^ .. 12.248 square inches. 





Comp. 

[nches ] 








LOADH 

Appukd. 


Per Horiz. Vertical 
Set. Defleo. Defleo. 


REMABK8. 




Lbs. ] 
10 000 . 


[nches Inches Inches 

.002 
.004 
.004 
.004 
.004 
.004 


• 




50 000 . 






10 000 . 






lOQOOO. 
10 000 . 










150 000 . 






10 000 . 






200 000 . 






10 000 . 






250 000 . 






10 000, 
280 000 . 






10 000 







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40 
Statement No. IS—Continited. 



^^^* Comn P^*" Horiz. Vertical Remahkh 

AppiiED. ^°»P- Set. Deflec. Dcflec. Remabiw. 

Lbs. Inches Inches Inches Inches 
290 000 

10 000 006 

300 000 .110 023 .055 

10 000 006 

310 000 

10 000 006 

320 000 

10 000 006 

326 000 

10 000 006 

330 000 Elastic Limit, 26 940 lbs. sq. inch. 

10 000 007 

340 000 

10 000 008 

350 000 

10 000 009 

355 000 

10 000 010 

360 000 

10 000 Oil 

870 000 

10 000 012 

380 000 

10 000 015 



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41 



Statement No. 13 — Continued, 



Loads n^^nn P®*" Horiz. Vertical 
Appukd. ^*>™P- Set. Deflec. Deilec. 



Bemabks. 



Lbs . Inches Inches Inches Inches 
890 000 

10 000 017 

400 000 

10 000 020 

420 000 

10 000 027 

446 800 Ultimate strength 36 480 lbs. sq. in. 



Column deflected to the east and downward . 

STATEMENT No. 14. 

Length of Column 10 feet . 

Sectional area 12.339 square inches. 

Weight 418 pounds. 



Loads n««,« P^r Horiz. Vertical 
Appukd. ^o™P- Set Deflec. Deflec. 

Lbs . Inches Inches Inches Inches 

lOOCk) 

50 000 .017 006 .009 

10 000 000 

100 000 .035 

10 000 002 

150 000 

10 000 003 

200 000 



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42 

Statement No. 14 — Continued, 



Loads rnmm P«r Horiz. Vert ReMAnira 

Applied. C°™P- Set. Deflec. Deflec. Remabkb. 

Lbs. Inches Inches Inches Inches 

10 000 004 

250 000 

10 000 004 

300 000 .109 014 .018 

10 000 008 

310 000 

10 000 009 

320 000 

10 000 010 

330 000 

10 000 010 

340 000 

10 000 .012 

350 000 Elastic Limit, 28 360 lbs. sq. inch. 

10 000 012 

360 000 

10 000 015 

370 000 

10 000 016 

380 000 

10 000 018 

390 000 

10 000 020 

400 000 .156 018 .015 



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43 



Statement No. Hr—Continued. 



Loads /!««« ^®^ Horla. Yertioal 
Applimd. ^™P- Set. Defleo. Defleo. 



Lbe. Inches Inches Inches Inches 
10 000 022 

405 000 

10 000 022 

410 000 

10 000 024 

420 000 

10 000 028 

430 000 

10 000 033 

449 100 Ultimate strength 36 397 lbs. sq. in. 



Column deflected to the west. 

After deflection reached about 4 inches, three or four rivets of upper 
west flange sheared . 

Flanges of concave side buckling. 

STATEMENT No. 16. 

Length of column 7 feet. 

Sectional area 12.265 square inches. 

Weight 291 pounds. 



Loads n««»« Pw. Horiz. Vertical 
Afplibd. *^™P' Set Defleo. Defleo. 



Rebcabkb. 



Lbs. Inches Inches Inches Inches 

10 000 
200 000 .054 014 .000 

10 000 002 

240 000 



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4A 

Statement No. 15~^ConHnued. 



Applied. ^o°»P- 8et. Deflec. Defleo. Remabks. 



Lbs. Inches Inches Inches Inches 
10 000 002+ 

252 000 

10 000 003 

264 000 

10 000 004 

270 000 

10 000 004 

276 000 

10 000 004+ 

282 000 

10 000 004+ 

288 000 

10 000 005 

294 000 

10 000 006 

300 000 

10 000 006 

306 000 

10 000 0061 

318 000 

10 000 007i 

324 000 

10 000 008 

330 000 



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45 
Statkmbnt No. Ih-^ Continued, 



^^^^^ Como ^®' ^o^^' Vertical Bemabkb. 

Applikd. ^^™P- Set. Defleo. Deflec. xv««a»b.i.. 

Lbs. Inches Inches Inches Inches 
10 000 008 

336 000 

10 000 009 

342 000 

10 000 009i 

348 000 

10 000 010 

354000 

10 000 Oil 

360 000 Elastic limit, 29 350 lbs. sq. in. 

10 000 Oil 

366 000 

10 000 >012 

372 000 

10 000 .013 

384 000 

10 000 014 

396 000 

10 000 016i 

408 000 

10 000 018 

468 000 Ultimatestrength,381571bs.sq.in. 

10 000 535 .000 

458 000 Sustained after above deflection. 

Column deflected to the west. 



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46 

STATEMENT No. 16. 

Length of column * 7 feet. 

Sectional area 11.962 square inches. 

Weight 284 pounds. 



LoAD$ n/>«».^ P^- Horir. Vertical _, 

Appukd. ^'"P- Set. Defleo. Defleo. BntAWCS. 



Lbs. Liches Inches Inches Liches 
10 000 

200 000 

10 000 003 

240 000 .067 016 .021 

10 000 005 

252 000 

10 000 005 

264 000 

10 000 005 

276 000 

10 000 006 

288 000 

10 000 006i 

300 000 

10 000 007 

312 000 

10 000 008 

324 000 

10 000 009 

330 000 

10 000 009^ 

336 000 



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47 

Statement No. 16 — Continued, 



Loads ^ Per Horlz. Vertlc*! m-WAPKa 

Applied. ^™P- Set. Defleo. Deflec. Bemabkb. 

Lbs. Inches Incbes Inches Inches 

10 000 010 

342 000 
10 000 OlOi 

afeooo 
10 000 on 

3^ 000 Elastic limit, 29 590 lbs. sq. in. 

10 000 Oil 

360 000 

10 000 012 

366 000 

10 000 012i 

372 000 

10 000 013 

378 000 

10 000 014 

384 000 

10 000 015 

390 000 

10 000 015i 

396 000 

10 000 016 

402 000 

10 000 017i 

408 000 



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48 
Statement No. 16 — Continued. 



Loads n«wi,» "^^^ Horlz. Vertical Rkwabkb 

APPLIED. C<^°>P- Set. Deflec. Deflec. R«wabk8. 

Lbs. Inches Inches Inches Inches 

10 000 019 

517 000 Ultimate strength,43 300 lbs. sq.in. 

10 000 2.11 .85 

472 000 Sustained after above deflection. 



Column deflected west and upward. 

Under load 466 000 pounds the column deflected considerably, and 
after which sustained 517 000 pounds with slight additional yielding . 

STATEMENT No. 17. 

Length of column 4 feet . 

Sectional area 12.081 square inches. 

Weight 164 pounds . 



Loads r««,«« ?«•*. _ 

APPLIED. ^™P- Set. Remarks. 



Lbs. Inches Inches 
10 000 

200 000 .031 

10 000 002 

250 000 .037 Flanges short, one end did not bear when experi- 

iQ Q^ Q^ ment began, about .007 inches off. 

300 000 .048 

• 10 000 005 

320 000 

10 000 007 

340 000 



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49 

Statembnt No. 17 — Continued. 



A^?^ C-P- 1*1. «-— »• 



Lbs. Inches Inches 

10 000 008 

350 000 .057 

10 000 009 

370 000 

10 000 010 

390 000 

10 000 014 

400 000 .072 

10 000 016 Flanges all come to bearing. 

410 000 

10 000 018 

420 000 

10 000 023 

450 000 .220 

10 000 .163 

500 000 .542 

10 000 476 

598 000 Ultimate strength, 49 500 pounds square inch. 



Column yielded upward, opening flanges between rivets, bulging 
outward on west side, and taking short (about 7 inches long) bend inward 
on under side. 



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5U 

STATEMENT No. 18. 

Length of column 4 feet. 

Sectional area 12.119 square inches. 

Weight 164J lbs. 



Loads 
Applied. 


Comp. 


Per 
Set 


Lbs. Inches Inches 


10 000 






50 000 






10 000. 




.001 


100 000 


.011 




10 000. 




001 


160 000 






10 000. 




.001 


200 000 


.025 




10 000. 




.002 


250 000 


.034 




10 000. 




003 


300 000 


.042 




10 000 . 




004 


320 000 






10 000. 




.004 


340 000. 




Elastic lim 


10 000. 




.004 


350 000 


.050 




10 000. 





.006 


870 000 






10 000. 




.007 


390 000 







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51 

SxATEKEirr No. 18 — Oontimted. 



A^SiSS,. ComP- ^ B""*-"- 



Lbs. Inches Inohes 
10 000 009 

400000 .065 

lOOOO.....*. .010 
410 000 

10 000 010 

420 000 

10 000 012 

425 000 

10 000 014 

430 000 

10 000 016 

440000 

10 000 021 

500 000 .557 

10 000 482 

621 000 Ultimate strength, 51 240 lbs. square inch. 



Took short bend inward on top at middle, and bending inward at 
bottom about 6 inches from middle. 



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52 

STATEMENT No. 19. 

Length of oolumn 8 inches. 

Sectional area ^.903 square inches. 

Weight 27Hb8. 



LoADg n«_^ Per. 
Apfum). ^™P- Set 



Lbs. Liohes Inches 
10 000 

50 000 .004 

10 000 002 

100 000 .007 

10 000 002 

160 000 .007 

10 000 002 

200000 .008 

10 000 002 

260 000 .011 

It) 000 002 

300 000 .013 

10 000 003 

350 000 .016 

10 000 004 

400000 .020 

10 000 007 

450 000 .062 

10 000 049 

600 000 .094 

10 000 080 



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-0 



53 
STATEiffSMT No, 19 — Continued, 



Applmd. ^"*P- Set Bbmabm. 



Lbs. Inches Inches 
600 000 .194 

10 000 171 

680 000 Ultimate strength, 57 130 lbs. square inch. 



The dimensions after the test were as follows : 

External diameter at middle 9 . 17 inches. 

" " «« ends 8.07 " 

Length 7.38 *' 

Openings, inside, between segments. 



I f^' Z J 

I za: ._J 



Bivets all holding well. 



STATEMENT No. 20. 

Length of column 8 inches. 

Sectional area: 11.903 square inches. 

Weight 27i lbs. 



aJSS). Comp. ^ B«.AB«. 



Lbs. Inches Inches 
10 000 

50 000 .002 

10 000 000 



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54 
SxATBMENT No. 20— OotUtnued, 



Loads p«-,« Per. 



Lbs. Inches Inches 
100 000 .004 

10 000 000 

150 000 .004 

10 000 000 

200 000 .007 

10 000 001 

250000 .009 

10 000 002 

800 000 .011 

10 000 002 

350 000 .018 

10 000 004 

400 000 .018 

10 000 006 

420 000 .019 

10 000 007 

425 000 .020 

10 000 008 

430 000 .023 

10 000 Oil 

440 000 .031 

10 000 019 

450 000 .050 

10 000 039 



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55 
Statbicemt No. 20 — Continued. 



APPLIID. ^°»P 8«t. B«aiA»KB. 



Lbs. Inches Inches 
500000 .088 

600 000 .185 

682 000 Ultimate strength, 57 300 lbs. square inch. 



After tested. 

Length 7 .41 inches. 

External diameter at middle 9 . 11 inches. 

Segments opening same as No. 19. 



In the above series of tests only one column, No. 14, gave way after 
the ultimate strength had been determined by shearing the rivets. 

Under loads exceeding ultimate strength, the columns yielded grad- 
ually, and, as the results show, would sustain a considerable load after a 
large permanent deflection had taken place. 

Elastic limit is given for 8 columns. 

For the others, where it is a question to discriminate what is per- 
manent set in the specimen, and what is simply compression at ends, I 
have not undertaken to decide. 

STATEMENT No. 21. 

WaTERTOWN AsSENAIi, JANUARY 19, 1880. 
TEST OP COMPRESSION OP TWO 6-8EaMENT FH(ENIX COLXTMNS. 

Columns placed in testing machine with flanges in position as shown 
by sketch. 



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56 
Statement No. 21 — Continued . 

Total length 25 feet, 2.65 inches. 

External diameter 11 .8 inches. 

Diameter throagh rivets 14 inches. 

Sectional area 18.30 square inches. 

Weight 1 561 pounds. 

Column tested with flat ends. 
Supported by two counter weights between ends. 
Compression guugings taken for fall length. 
Vertical and horizontal gaugings taken at middle. 



Loads Total Per. Horiz. Vert. 
Apflisd. Comp. Set Deflec. Deflec B«mabk8. 



Lbs. Inch. Inch. Inch. Inch. 
20 000 

200000 .115 

20 000 006 

300 000 .178 

20 000 010 

820 000 .191 

20 000 Oil 

340 000 .205 

20 000 012 

350 000 .211 014 

.009 
20 000 013 

370 000 .224 

20 000 014 

390 000 .237 

20 000 015i 

400 000 .244 010 

.001 

20 000 016 

.003 

420 000 .257 



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57 
Statement No. 21— Continued. 



Loads rnin^ **«• Horlz. Vertical 
APPLWD. ^°™P Set. Deflec. Deflec. 



Lbs. Inch. Inch. 

20 000 017 

440 000 .271 

20 000 019 

460 000 .279 

20 000...... .020 

460 000 .286 

20000 021J 

470 000 .293 

20 000 023 

480 000 .299 

20 000 025 

490 000 .307 

20 000 026i 

500 000 .315 

20 000 027J 

510 000 .323 

20 000 028 

520 000 .329 

20 000 030 

530 000 .338 

20 000 031 

540000 .345 

20 000 032 

550 000 .354 

20 000 035 

560 000 ..163 



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68 
Statbmkiit No. 21 — Continued. 



Loads 
Applxkd. 


Oomp. 


Per 
Bet. 


^r. S5r ««— 


Lbs. 


Inch. 


Inch. 


Inch. 


Inch. 


20 000 . 




.038 






570 000 


.371 








20 000. 




.041 






580 000 


.382 








20 000, 




.046 






590 000 


.392 








20 000 . 




.051 






600 000 


.406 




20 000 . 




.057 





Stood over night nnder 200 000 lbs. load. 


610 000 


.410 








20 000 . 




.057 






620 000 


.418. 




.076 


.027 


20 000 . 




.068 


.055 


.015 


630 000 


.440 








20 000 . 




.074 






650 000 . 






.311 
.262 


.334 


20 000 . 




.148 


.270 


659 000. 








Net strength, 36 010 lbs. sq. in. 


20 000 . 






.939 
1.231 
1.951 


1.206 


604 000 . 






1 616 Load sustained. 


20 000. 






2.776 


538 000. 






2.494 
2.499 
3.224 


3.606 *• 


20 000 . 






3.741 


514 000 . 






4.826 " 











Deflected downward and sideways. 



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59 

STATEMENT No. 22. 

Total length 8 feet 9.5 inches. 

External diameter 11 .8 inches. 

Diameter through rivets 14 inches. 

Sectional area 18.3 square inches. 

Weight 544 pounds. 

This column and No. 21 formed one column 34 feet long, originally, 
cut in two at the Arsenal to admit being tested in the machine. 

Tested with flanges in same position as No. 21. Column not counter- 
weighted between ends. 



Loads 
Applikd. 


Tot%l 
Comp. 


Set. 


Lbs. 


Inch. 


Inch. 


10 000 






200 000 


.045 




10 000. 




.001 


300 000 


.067 




10 000. 




.002 


400 000 


.090 




10 000. 




.004 


450 000 


.103 




10 000. 




.005 


470 000 


.107 




10 000. 




.006 


490 000 


.113 




10 000. 




.008 


500 000 


.115 




10 000. 




.0081 


510 000 


.118 




10 000. 




.009 


620 000 






10 000. 




.009 



BXMABX8. 



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60 

Statement No. 22 — Continued 



ix)ADB ^ ret Kkmabm. 

Applied. ^^*"*'- get 



Lbs. Inch. Inch. 
530 000 

10 000 010 

640 000 Elastic limit, 29 510 lbs. per sq. in. 

10 000 Oil 

550 000 .129 

10 000 014 

560 000 .134 

10 000 014i 

670 000 .137 

10 000 016i 

580 000 .141 

10 000 019 

590 000 .145 

10 000 020 

600 000 .149 

10 000 023 

610 000 .153 

10 000 025i 

620 000 .160 

10 000 029 

650 000 184 

10 000 .047 
772 000 Ultimate strength, 42 180 lbs. per sq. in. 



Column deflected downward and slightly sideways. 

JAMES E. HOWARD. 
Watertown Arsenal, Mass., 



Digitized by VjOOQIC 



AMERIOAlir SOCIETY OF CIVIL ENGINEEES. 

INBTITUTED 18B.1. 



RoTB.~Tbl« Sodety U not reiponiible. m a body, for the facts and opiniona advanced in any 

of its publications. 



ccxxxm. 

(Vol. XI.— Febrnary and March, 1882.) 



DISCUSSIONS 

UPON 

WROUGHT IRON COLDMNS, TESTS AND FORMULAE. 

None. [See Paper GCXXXn immediately preceding, Expebimemts upon Phoenix Ooluukb : 
by OukBKK, Bbeyks & Ck>. See also Paper CCXII, Vol. DC, p. -447. The Stbsnoth of Wrought 
Iboh C0LUMW8 : by G. BotracAKKN.] 



Discussions by G. Bouscaben, Theodobe Coopeb, D. J. Whtttemokk^ 

Chablbs E. Emeby, Db Vol^on Wood, C. L. Stbobel, A. S. C. 

WuBTBLE, WniUAM H. BuBB, Mansfibld Mebbiman, 

C. L. Gates, James E. Howabd and 

Thomas C. Cijabke, 



Digitized by VjOOQIC 



62 



Discussion by G. Bouscaren, M. A. S. C. E. 

The strength per square inch of a wrought-iron post depends prin- 
oipally on the three elements : 

1. Batio of length to diameter. 

2. Shape of the cross-section. 

3. Quality of the metal. 

To these may be added as incidental causes of variation : 

4. Workmanship, where the post is made of several parts riveted or 
bolted together. 

5. Conditions in which the load is applied. 

A formula expressing corretly the law governing the resistance of 
posts must necessarily contain representative factors of elements 1, 2 
and 3. 

In the empirical formula deduced from Hodgkinson*s experiments 
p f 

by Gordon -q- = /T\^f *°^ ^ *^® coefficients dependent re- 

spectively upon the ultimate resistance to crushing and on the modulus 
of elasticity of the metal ; the shape of the cross-section is left out alto- 
gether. The correctness of the formula must, therefore, be limited to 
solid posts of circular and square shapes of cross section, which were 
the types used by Hodgkinson in Ins experiments, the constants / and 
a being determined experimentally for every different kind of iron. 

p f 

In Gordon's formula, modified as proposed by Rankine -^ = — - — ^ 

l+a- 

The shape of the cross-section is represented by the radius of gyration 
r and the formula can be made to agree very approximately with the 
results of experiments by a proper selection of the constants. This was 



Digitized by VjOOQIC 



63 





ii 


- » 

il 


i 8 I 2 g 3 1 8 8 § 1 2 1 1 

1 1 1 1 1 f + 1 t t + 1 + + 


5 § § 1 
-^ s s 

1 i 1 1 




1 


i '^ 


22iiss3=:i5iill 

! 
S s § s i S § g S Is i g 1 § 


s s 2 2 
^ IS s s 

5 5 5 5 

5 S S § 

§S 8 5 S 

i § S § 

S 8 5 IS 






s 
a 

1 


! 3 
1 

-f- 
II 

+ 

II 


§ 

Ii 
1 

2 


^ « 


III 


§ i 1 i " i 8 


g I 


1 


■: * 

8 * 




1 1 § § § § § 1 i 1 § i § i 


§ i § 1 

S IS 5 S 





III 
33I 


1 1 i I i 1 1 1 1 1 1 1 1 i 


i S S 1 

Ok o» o» o> 




9 09 




«o « 




i 






it 


■g,..,... 




■ 
t 


aaaassssssssss 


t- t- •* •<• 






JS 2 5 2 











Digitized by VjOOQIC 



64 



Vr, 1 1 1 1 1 1 1 1 1 I 1 


i_ 






,E:?r^:-::-L 


- j- p — 


\ l1 

1 \ ' \ ' 


— 1 — 'HH — 




1 




b 1 ' 




^ M i 


_4 


^ ! 1 \ 




^ -1-1- -ll^ " 








^{jH" 1 ■ V - ^ 1 






- [- 


j- .1, ._^ . 


_._. !r_L n 


h ill 1 






- I H~ 


^ , ; t , 


; 


*^^ 1 1 i 


t 


^' L,[' 




' ' Ml 




-• : L ,rj4 1 1 








V, Ml pi 1 






i j 1 _ 


1 1 j(j t 




V \tt'' fjMX[: " 


1 


' 1 5^' i^.'^ 


i I , 


h i r^' ; ^ 


^ -k, ' ' i 1 


J_L_L. _ ii _U-J_J 


"^^^ 1 1 : ' 




1 ; 


-i.-i 4 -i-j. - - . ' 


! 1 

- J -J-l -1- ;. ♦- 


1 1 


5 ^ 5 
? s s 



a^d^ytAz/fO ^rj9i'/>zor/^ //f /^c^f/r^^ ^r/9 J if. f^. 



Digitized by VjOOQ IC 



65 

shown by the tests made for the Cinoiimati Southern Railway, bat may 
be illustrated in a much more satisfactory manner from the experiments 
of Mr. Clarke and associates, which, being all made on columns built 
of the same iron, in the same shop, and tested in a machine of excep- 
tional precision, may be considered as substantially free from the in- 
fluences due to differences in the workmanship and manner of testing. 
The shape of the posts being also uniform, the principal factor of yaria- 
tion here is the length. 

Column 7 of the accompanying table gives the values of / deduced 
from the results of experiments 1 to 18, inclusive, with Bankine*s for- 
mula/=4_ (i. y M 

The gradual decrease of the values obtained, from 46 264 for post No. 

1- 
1 to 38 908 for post No. 15, indicates that the value ^ftu^ assumed for 

a in the formula is too large. Column No. 8 gives the value of / 

corresponding to a = =^ / _ ( 1-u — — | 

^ ^ 100 000 y - ^ V ^ 100 000 r». / 

These are remarkably uniform, the extreme variation from the 
average (38 000) being less than three per cent. 

With this average of 38 000 assumed for /, and « = ^/^^ q^- iii the 

p 
formula, the calculated values of -^ will agree very nearly with the 

actual results of the tests, as a comparison between Columns 5 and 9 of 
the table will show. It is remarkable indeed that the differences be- 

p 

tween the actual and calculated values of —^ should be less than the 

o 

differences between the resistances as given by two tests on similar posts. 
This is seen at a glance by a comparison of Columns 6 and 10 of the table. 

The accompanying diagram illustrates further the close agreement 
between the formula and the experiments. 

The sudden divergence noticeable for posts 17 and 18 is explained by 
the fact that they did not fail by bending, but by a buckling of the 
metal. 



Digitized by VjOOQ IC 



66 



Discussion by Theodobb Cooper, M. A. S. C. E. 

The very oarefnl tests made upon wroaght iron columns of different 
forms under Mr. Bousoaren's direction, have been of great service to 
the profession. They drew attention to the defects existing in the best 
of our columns in use at that time (1875), and have produced a great 
improvement in the forms, proportions and workmanship of the columns 
now used by the more careful of our designers and builders. 

It does not seem a matter of much doubt, that were similar tests made 
upon the columns now used, undQr as disinterested an examiner, we 
should have far better results upon all of our columns. 

When it is appreciated that these were the first general tests made 
upon modem columns of large sizes, the great benefit to our practical 
knowledge becomes evident. 

With the exception of a few isolated experiments, made by a couple 
of our bridge building firms for their own purposes, we had no tests later 
than those made by Hodgkinson for the Conway and Britannia tubular 
bridges. 

The experiments upon Phoenix columns made at Watertown Arsenal, 
are also a valuable addition to our stock of knowledge upon well made 
columns of varying dimensions. 

The well known Gordon's formula — 
P 36 000 



"^ 3 000A* 



: crippling strain per square inch. 



which has been generally assumed as the standard of strength for all 
wrought iron columns with square ends, had its numerical constants de- 
rived from a series of experiments made by Mr. Hodgkinson upon small 
bars and plates, whose cross-section varied from one inch square to that 
of a rectangle 5} inches by one inch. 



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67 

It was very reassnring to find from Mr. Bonsoaren's experiments that 
a formula based upon such small specimens gave results as near as it 
did to the experimental ones. 

Though the above formula was only intended to represent the strength 
of columns with a solid square or rectangular section, it has been gener* 
ally applied to columns of all shapes of cross-sections. 

The general form of the above formula was derived in the following 
manner : 

The direct crushing strain upon any section of a column is represent- 
ed by 

P = t otal load. 

S = Sectional area, (1.) 

Any tendency to bend of a flexible column, free at the extremities, 
would increase the above crushing strain upon the concave side of the 
column, and relieve it upon the convex side. Analysis has shown that 
this increased strain due to the bending is theoretically equal to 

~ — -^for the section at the centre of the column = ^ .^. 

where P = total load on column, 8== Sectional area, 

/ = length, /moment of inertia, and X the compression per square 
inch for a luiits length. This is identical with the formula for limiting 
strength given by Euler for long flexible columns which fail solely by 

EI 
flexure P =zic* -j—- , if we reduce by substituting for E, modulus of 

elasticity, its value -^— , /' being strain per square inch due to bend- 
ing only. 

Summing equations 1 and 2 for total strain /, and representing the 

numerical quantity — - by the constant a ' we get 

P f 

~cr= — I - (3) Rankine's formula. 

^ l + a'-ii 



Or for rectangular columns only 
P f 






(4) Gordon's formula. 



r being radius of gyration and h least side of rectangle. 



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68 
From the experiments of Hodgkinion upon small bars and plates of 
wrought iron, Gordon determined the value of a to be oKqq ^^^ square 

ended colunms. 

Bankine from the relation 

Mom. Inertia of a square = -^-9-= Sr* or 
^ 1 = 12 r « or 

h __ /« 
3 dob A« 36 000 r« converted Gordon's factor into 36 000 

for his own formula . 

The numerical factors being obtained from the same experiments, 
both formulfB should be equally true for square or rectangular solid 
columns. 

For any other form of column Gordon's formula can not be con- 
sidered as applicable. Bankine's being of a more general form should 
be more nearly correct, and from the closer coincidence of the results ob- 
tained by Mr. Bouscaren, we are reassured of its greater correctness. 

It, however, has not been generally used, no doubt from the apparent 
difficulty of obtaining the radius of gyration of various sections. This, 
however, can be readily overcome by substituting in the Bankine's form 
the average value for the radius of gyration of each particular form of 
cross-sections in terms of the least side or the diameter. 

The numerical constants a and a ' being derived from experiments on 
small bars, would very probably be different for columns of practical 
shapes and sizes. 

Theoretically they represent a factor of the compression of the ma- 
terial, supposed fully elastic. Practically they represent a certain in- 
fluence of the ultimate (not elastic) compression and extension, and also 
the influence of the fitting of the columns in the testing machine, includ- 
ing the squareness of the ends and comparative axial direction of the 
applied strains. 

As the ultimate compression is not strictly a factor of the modulus 
of elasticity, but rather a factor dependent upon the quality of the iron 
as to ductility, we should expect the result pointed out by Mr. Bouscaren : 
that the uUimate resistance does not appear to be dependent upon the 
modulus of elasticity. 



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69 

As it would appear to be relatively easier to bring the ettds of large 
pieces to a square bearing, and the axis of strain more coincident with 
the axis of large columns than with the small bars experimented upon 
by Mr. Hodgkinson, we could reasonably expect in a new formula a 
smaller value for the constants a and a'. In examining and comparing 
experiments upon columns of different forms and makes, we must bear 
in mind fche possible variations that will occur from practical considera- 
tions, some of which have been pointed out by Mr. Bousoaren. 

Ist. The proportion of parts, such as the relative thickness of the 
metal to the size of the cross-section ; (both Hodgkinson and Bouscaren's 
experiments show that a flat surface exceeding thirty times its thickness 
in breadth, will not be able to sustain its required compression without 
crippling)— the proper size and spacing of lattice bars, when used— the 
proportionate number of rivets at different parts of the column to resist 
the longitudinal shear due to the bending of the column or an unequal 
distribution of the pressure. 

2d. The character of the iron as affects its resistance to crushing. 

3d. The condition of the plates, channels or other forms as they come 
from the rolling mill ; and the necessary work to be put upon the pieces 
to take out the bends, warps and buckles that are almost always to be 
found in them. The fearful ordeal of the straightening sledge or drop 
leaves the pieces in a straighter condition, but at the expense of initial 
strains or a want of homogeneity in the resisting power of the metal. 

4th. The character of the workmanship as shown in the riveting, the 
planing of the ends truly parallel and at right angles to the axis of the 
column, and the straightness of the column as a whole. 

5th. The defects due to an aggregation of several pieces of possibly 
varying resistances to crushing and bending, thus producing a want of 
symmetry in the strength of the column. This being the probable expla- 
nation of the anomaly of columns like Nos. 13, 19, 21, 32 and 42 of Mr. 
Bouscaren's experiments, failing in their apparently strongest direction. 

6th. The indefiniteness of the crippling point as determined by dif- 
ferent observers, and the different manner of making the tests. 

*' The care taken to have the strains of compression pass exactly 
through the axis of the column " and '' the ends brought to a good bear- 
ing," as noted by Mr. Howard, would have a very important influence 
upon the flnal result. The rapidity of making the test would also pro- 
duce a variation in the recorded strength. 



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70 

7th. The relative moduli of olastioitj of the columns ; though the ef- 
fect due to this factor would be more apparent in tests for limit of elas- 
tioitj than for ultimate strength ; for as before remarked the elongations 
and compressions of the material at or near the crippling point would be 
more dependent upon the ductility than the modulus ; but within the 
elastic limit, the bending strain would undoubtedly be largely depend- 
ent upon the modulus of elasticity of the column. 

The difficulty of recognizing the varying influences efifecting the 
strength of columns of various forms and dimensions, compels us to the 
necessity of accepting averages^ the reliability of which is largely de- 
pendent upon the number of our experiments. 

Upon Diagram No. 1, Plate I, we have plotted with reference to the 
ratio of lengths to diameters all the most reliable experiments of Messrs. 
Hodgkinson, Bouscaren and Howard upon square-ended columns, with 
some few miscellaneous ones collected by the writer ; only omitting such 
ones as were plainly (from our present knowledge) defective in construc- 
tion. 

Upon Diagram No. 2, Plate n, we have plotted the same experiments 
with reference to the ratio of the lengths to the least radius of gyration. 
This being a much more reliable method of comparison of columns of 
various cross-sections ; for we not only eliminate the influence of the 
shape of the cross-section, but also have a definite dimension as a refer- 
ence, which we have not in accepting the least side or diameter. For 
example, in a Phoenix column the nominal dimension used for a four 
segment column is the external diameter of the shaft, but for a greater 
number of segments the least dimension would include a portion of the 
flanges ; or if we still cling to the diameter of the shaft, why, in channel 
columns, should we not also accept the distance over the webs instead of 
over the flanges. However looked at, there is no positive comparison of 
different sections but by the radius of gyration, and we may consider 
that twice the radius of gyration is the '* effective diameter '\ of any sec- 
tion. 

The relation existing between the least dimension and the radius of 
gyration of the usual sections is given below : 



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71 
TABLE No. 1. 



GAom Skotxox. 



r» : h*. 



A' 



Solid Rectangle ^^ io 



Box Column I r*— 

I 

I 
Open Col. of Channels.; r'^ 

i 
Solid Circle 

Hollow (thin) Circle. 

Phoenix Col 

Cross + 

Amer. Co/b Col 



- apppox. 

A* 
7.8 



'"— 16- 



r: h. 



Comp«r«t(Ye 

Tftlueff of a for use 

in OordOD'a 

Formula. 



8.46 



•'-— ^approx.1 
2.7 



3000 

1 
6t;00 

J_ 
4930 

_1_ 
2250 



•• — '-y approx 

7.6 

^* 
24 

A« 
"""11.6 



h 

2.82 


approx. 


1 
4600 


h 
""2.75 


" 


1 

4760 


h 




1 


4.9 




1600 


h 
"" 8:4 


" 


1 
3100 



The fractions in the second member of the equations, tinder the third 
oolomn, represent the comparative lengths of colnmns of different cross 
sections of equal strength. For example, the relative length of a Phoenix 
Golunm and ah American Company's Column of the same strength would 
1 1 



be 



or as 34diams. is to 27^ diams. 



2.75* 3.4 

This shows the importance of referring to the ratio of the radius of 
gyration instead of trying to compare by the ratio of diameters between 
columns of such unequal resisting capacity. 

Beturning, therefore, to diagram No. 2, as a fair comparative view of 
such tests as we possess, it will be seen that the diagram can be divided 
into three different zones marked A, B and (7, which would appear to 
mark three different class of columns somewhat similar to that pointed 
out by Hodgkinson for cast iron columns. 



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72 

In zone A, the rasistanoe of oolnmns from 1 to 50 radii of gyration 
seemu to drop along an inclined strip bounded by lines mnning from 

59 000—38000 
and 46000—27000 

In zone B, from 50 to 120 radii of gyration, to be bounded by lines 
nearly horizontal, mnning from 

37 000—35150 
and 26 000— 25 000 

In zone C, beyond 120 radii of gyration, the lines descend with a de- 
creasing rate and converging as they approach the higher ratios. 

This apparently anomalous restdt, of different laws of strength for 
colamns of different lengths, noticed by Hodgkinson in cast iron 
columns, and partially visible in the Watertown experiments, is here 
clearly shown to be true of all the experiments upon square ended 
columns. If we could not determine the reason for this change of 
strength and correct our formulae to provide for it, we would be justified 
in adopting '* separate formulae for long and for short columns,*' as is 
suggested by Messrs. Clarke, Beeves & Co., in their report of the Water- 
town experiments. 

We will endeavor below to offer an explanation for the occurrence of 
the three zones of action ; from which it will be seen that our previously 
accepted theoretical formula is defective in omitting a very important 
factor. 

Zone A, comprised the limits wherein the columns have failed solely 
by crushing or failure by flexure cannot be expected. The writer believes 
the inclination of the crushing line to be simply due to the operator 
waiting for the same amount of visible crushing in a short as he would 
in a longer column. 

Zone By is at first inspection still more anomalous as it shows an 
almost equal strength for columns varying from about 20 diameters to 
42 diameters in length, which would lead us to believe at the first view 
that this zone is also free from failure by flexure. Upon consideration 
it is evidently/ due to the manner of testing the columns^ or in other words, 
our theoretical deductions are defective, t^^^^n applied to experiments made, 
as all of these were, between two opposite and rigidly parallel faces of a 
testing machine. 



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73 



Lei Fig. 1 represent a square ended column being compressed be- 
tween two rigidly parallel faces A and ^ of a testing 
machine. Upon any tendency of the colamns to bend 
to the right as shown by the dotted lines, the centre of 
pressure is also transferred towards the right, instead 
of continuing to act through the axis ; we thus get a 
movement resisting the tendency to bend, and which, 
within certain limits, will counteract the flexure that 
would otherwise cripple the column. 

In very few of our practical applications of square 
ended columns could we expect this rigid maintenance 
of parallelism of the bearings, and therefore we would 
Fio. 1. not be justified in assuming these tests as strictly ap- 

plicable to practical cases. 

The first part of test No. 3 of the Watertown experiments illustrates 
the principle above mentioned very clearly. This column was tested 
with hemispherical ends, one of which was found to be imperfect so that 
the bearing point was half an inch out of centre. After this column had 
been strained to about 20 000 lbs. per square inch, and had taken a per- 
manent bend of -|-0.102 inches the eccentric head was reversed and the 
strain increased to 23 700 lbs. ; this shifting of the centre of pressure re- 
moved the first permanent bend and gave it one* of-:-. 008 in the opposite 
direction. Thus clearly illustrating the effect of resisting or reversing 
the bending tendency, by any decentralizing action of the centre of 
pressure, when, as shown by Fig. 1, it is towards the same direction as 
the original flexure. 

Zone C, comprises but a few experiments upon large columns, and 
hence cannot be considered so satisfactory as the results shown in A 
and B, We are, however, justified from what data we have, in believing 
that at some point at or beyond 120 radii of gyration the sections of the 
columns become so small in reference to the length that the resisting 
moment of the ends diminishes rapidly and reduces to nothing finally. 
Hence we should here expect, as shown by the experiments given in this 
sone, a descending curve represented by our theoretical formula 

S 1+ aja 



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74 



Pin-Ended Columns. 

We have confined our remarks heretofore to square-ended columns 
ezclusiyelj, as the great mass of our experiments are upon the latter kind 
of columns. 

It is to be regretted that we hare not a more extended series of exi>eri- 
ments.upon pin-ended columns, for both the theoretical formulae and 
the practical results of the tests we possess are unsatisfactory. 

The formulae for pin-ended columns 

P f 

*S~= l+ial^ (Gordon's.) 

P f 

"^= 1 -f.2 a/a (Bouscaren) 

"?» 
would appear to be wrong as compared to the usual one for square-ended 
columns ; for at very high ratios the efifect of the ends sl\ould be identi- 
cal, as the square ends would be practically reduced to round end& The 
formulae, however, give results for the high ratios, 2 to 4 times as great 
for square-ended columns as for the pin-ended ones ; instead of the lines 
of strength converging towards the higher diameters, they are constantly 
diverging, which does not appear reasonable. 




Fig. 2. 

Practically, the writer believes, the strength of pin-ended columns 
would be found to be somewhat governed by the diameters of the pins 
(aside from the crushing effect upon the bearings) and the closeness of 
their fit to the pin hole. For the same resisting action against bending^ 
as has been mentioned, under square-ended columns would, no doubt» 
here occur to the extent of the frictional moment about the pin. The 
round-ended column cf, is the only one of those sketched in Fig. 2 which 
would be free from this resistance to flexure. 



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75 

If we possessed a sufficiently extended series of experiments upon 
round, pin and square-ended columns, we would probably find that those 
on round ends gave the closest correspondence to our theoretical 
formula, and the others could be derived from it^by adding a factor rep- 
resenting the resisting influence of the ends. Such a formula would not 
only be rational, but would point out more definitely the efiects of the 
ends than those we now have in use ; where as much weight is given to 
the squareness of the ends upon a column 100 diameters long as to a 
column 10 diameters. 

As it may be far in the future that we can possess such a complete 
set of experiments, we are justified in attempting temporary formulse to 
represent the present state of our knowledge. 

Tebcporaby Fokmul^ por Wrought Iron Columns.— It will 
appear plain to those who examine our diagrams, that when we 
consider only" the range of the zones A and B, the result of the experi- 
ments can be represented by numerous formulae as long as we introduce 
proper constants. But in order for our formulse to approximate to the 
truth, we must extend their range over the whole field of our experi- 
ments. 

Square-Ended Columns. — ^From our remarks upon the effect of the 
squareness of the ends of the columns to prevent the bending tendency, 
we may consider the effect to be equivalent to a certain reduction of the 

effective length of the column or of the ratio JL 

r 

If we therefore represent the ratio — by R in our formula and call m — 

r "^ r 

= n the proportionate reduction of the total ratio by the effect of the 

squareness of the ends, our theoretical formula would now be 

_^ _ / (5) 

S ""l+a (i?-n)» 

Applying this formula to the experiments plotted on Diagram No. 2, 

1 
we get the following numerical values : /" = 36 000, n = 80, a = jgQQQ or 



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76 

the foUowing formula : Z ==, . ^^ ^^ _ 

1+ ^ («) 

18 000 

as representmg very closelj the experiments on Phoenix columns. 

The minimum curve of the experiments upon large sized columns 

would appear to be represented very closely by the formula 

_P_ 30 000 ,. . 

5"" .,(Jf:^0)i ^ '^ 

■^ 18 000 

These two formulas are plotted upon this diagram, and their coinci- 
dence with the experiments would seem to justify us in accepting them 
for all columns where the ends are held rigidly square^ as were those in 
the testing. 

For Pin Ended Columns we should have, if our claim previously 
made in regard to the resisting moment of the friction is correct, a 
formula like equation (5), but with a lower value of n. 

For Bound Ended Columns, where there is no resisting moment, the 
same equation (5) should apply, by making n = o. 

In the following table we have determined the value of / for the dif- 
ferent classes of columns from the following formulae: 

P f 
Square Ended Columns ^ = n^ZisiDs ^^'^ 

^ "^ 18 000 
p f 
Pin Ended Columns t^ =- /„ ^^. {d.) 

^ 14- t ~ J^ 

'^ 18 000 
p f 
Bound Ended Columns ^ = v, («•) 

^ 18 000 



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77 



§§MMMMMM 




I 
1 

I 



§ i § 



S 8 S 









8 

i 

I 



r« o c« eq 



5 8 



S S ql S ^ S 



■« Ok t> 



s^^^l^lS'ls^^s^ 



Ok « 



=1 

gS 



a 




f 



I! 

£| 
^1 
Is 

; II 

i iss 

•2 

|i 

I 

i 



I 

6 

a 



I 

.a 






N 

^ 

J 






Digitized by VjOOQIC 



78 



d 

I 



ill 

•i! 



S g s 

O f-l iH 



S £ 



§ I 



s s 



1^1 






§ I 



I I 



5 



1 






2 S 



3 S 



S S 9 2$ S 



5* 



S '• 



I 



7 

I 



I. 



I 

2 
I 



I 



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79 
TABLE No. 4. 



KADB BT. . 


Kind 

of 

Oolnmn. 


Form 

of 

Beerlngf. 

Sqnire. 

«« 
Pin. 


BATioa. 


FormnliB 
need 
tot f. 


Streinper 
Sqoere 

Inch by 

Bxperl- 

ment. 

80.300 
83.300 
80.000 
36.600 


Value of/ 
aa derired 


I 
d 

36 
84.1 
41.6 
30.9 


98 
84 
103 
98 


firomEx- 
perimenta 


Mr. BoQMMren 

M 
«< 


Box Core. 


(c.) 


80.740 
88.346 
80.810 
30.600 


General aremge.. 


81.600 



















Greatest variation 30.600 to 33.246, or 5 per cent from average. 
TABLE No. 5. 



Mr. Booacaren. 



Kind 

of 

Column. 



Op'n Col's 



Form 

of 

Bearinga. 



Square. 



Pin. 



Ratios. 



33 

37.6 

37.6 

88 

46.6 

61 

84)i 



60 
78 
73 
90 
180 
188 
76 



^1^ 


Strain per 

Square 

Inch by 

Expert. 

ment 


(«.) 


83.800 


" 


39.600 


" 


83.400 


" 


83.800 


m 


18.000 


«t 


33.128 


«4 


81.700 



Value of/ 
aa derired 
from Ex- 
perimenta 



81.680 
29.630 
83.800 
83.480 
27.410 
37.394 
84.940 



Average for square ended colnmns = 31 .470. Variation from average 
is only 6 per cent. For the pin ended colnmns the variation is mnch 
greater, and especially between the two columns of nearly same number 
of radii in length, which would relieve the formula of the blame. As 
these three columns were of different forms and material, made at differ- 
ent shops, and tested at different places, we can consider that the want 
of correspondence to our formulse, which have been so close for so many 
other columns, is rather due to other circumstances, perhaps largely to 
the relative closeness of the fit of the pins. 



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80 
TABLE No. 6. 



SXPSBDmiTS 

ICadbbt 


Kind 

of 

Colomn. 


Form 

of 

Besrings. 


Bados. 


Formnln 
Used 
for/. 


Strain per 
Bqniire 
Inch by 
Experi- 
ment 


Value of/ 
as Derived 


I 
d 


I 


firom 
Expert, 
ment. 




Keystone. 
•< 

*4 


SqoAre. . 
Round . .. 


21.7 
20.3 
37.6 
.34.1 
20 
36.1 


60 
64 
186 
96 
66 
98 


(0 


30.000 
82.000 
27.800 
30.000 
36.960 
22.000 


29.880 
31.640 
32.470 
30.426 
36.720 
83.788 



Oanend average equals, 82.200, with a maximum variation from the average of 11 per cent. 

No donbt, a more extended series of experiments upon the different 
olasses of columns, wonld enable ns to adopt constants still more exactly 
representing the strength of these columns. And, as before remarked, 
columns, as now made, with the light thrown upon their weak points 
by Mr. Bouscaren's experiments, would undoubtedly give better results 
than those recorded above. It would also be reasonable to expect that 
the value of a would vary with different classes of irons as well as that of 
the constant/. 

Fron the result of our comparison, it seems proper to assign to / in 
formula (c) {d) and {e) the following values : 

For Phoenix columns, /= 36.000 
•' Amer. Co.*s " /= 30.000 
" Box and open " / = 31.000 

FormulfiB c, d, and «, as before explained, can be reconverted into 
formulsB containing the ratio -r instead of — ^y the use of our pre- 
vious table No. 1, but the formulse then must be applied to a special 
form of column only, instead of being general as are c, d, and e. 

Calling ■--= J7, and using the values from Table 1, we get the follow- 
a 

ing special f ormulse : 



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81 

For Phcenix Columna : 

P 36000 

Square Ends, ~^- = '^.(H^^ » 

"^ 2400 
36 000 



Pin Ends, 



^ 2 400 '^ ' 



BonndEnds, " = 



26 000 



^ 2400 



For Amer. Co.'s Columns : 

p __ 30000 

Square Ends, -g- - " (£r— 24)'* 
"^ 1600 



^. ^ . » 30 000 . 

Pin Ends, = (g--:iOp\(7) 

■*■ 1600 ' 



Bound Ends, " = - 



1+ ^ 



1600 
For Box or Square Columns : 

P 31 00 _ 

Square Ends, ^= (H—S2) * 

■^ 3000 

P _ 31000 

Pin Ends, ^ - (g — 137' 
■*■ 3000 

For Open Columns of Channels : 

P 31 000 _ 

Square Ends, ^ = — JH— SO) ^ 

2475' 

\(9) 
P 3 1000 ( 

Pin Ends, ^= (£/-12) ^ 

"^ 2 475 



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Notb": The valtie of / has no relation to the omshing strength of a 
short column, as is offcen claimed for this factor in Gordon's formula. It 
represents here what it did in Gordon's formula, a numeriocU constant, to 
take the place of the factor / in our theoretical formula — / being 
theoretically the greatest strain upon any unit of metal from the applied 
load. 

Limit of Ei<AsnoiTr. 

In examining into the results of the experiments with reference to 
the elastic limits, we find a much greater variation than is shown by the 
crippling strain. This we should expect in columns containing any of 
the before mentioned defects of material or workmanship. The full 
influence of these defects would be visible in tests for the limit of elas- 
ticity, but only partially in those for crippling stress as the flow of the 
metal would accommodate itself somewhat to any irregularities after the 
elastic limit was passed. 

The results given for the elastic limits in the tests made at Water- 
town, do not appear to the writer to be justified from the records as 
given. It is not dear to him what rule was adopted as the guide to 
locate this point By an analysis of the data in those experiments, 
where the detailed compression is fully recorded, the elastic limit would 
appear to be much lower than that given in the tables. It is a difficult 
matter to determine the elastic limit in compression experiments, but 
it is better to err by placing it too low than too high. 

Taking Mr. Bouscaren's experiments as more general, containing a 
greater variety of columns, and more nearly representing the cruder tests 
which columns would receive in actual structures, we have determined 
the values of Z^, corresponding to the limits of elasticity by the formulsB 
c, cT, and e. 



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83 



TABLE No. 7. 

YaIiITBS op /i , IN FoBMULiB C, d, AND 6, FOB THE LiMIT OP ElASTIOITT. 



Kind of Column. 


r 

66 
60 
64 


/i. 

14 600 

17 100 

18 740 




Keystone. 


Average value of /, , for limit of elatticity 
— 17 740 IbP. 

Minimum value, = 12 170 lbs. 




96 


12 170 






98 


22 940 






186 


21 000 




American Co/a 


81.8 


18 470 


Average value of/^, ^18 686 lbs. 




81.6 


28 000 


Minimum " " *' — 18 470 " — 




101. 


16 080 


46 % of / the coefficient of crippling. 




102.6 


18 960 


Variation of minimum from average 




106 


18 260 


-28% 




110 


24 940 






166 


17 100 





Square or Box. 



Open. 



84 

98 

98 

102 



14 960 Average value of /i. — 16 880 lbs. 

18 670 I Minimum " " — 14 960 — 48 % of / 

16 870 the coef. of crippling. 

16 820 , Variation of minimum from average = 9 % 



•60 
72 
76 
90 

130 



22 420 Average value of /i, = 21 688 



23 000 
23 100 
21 160 
18 270 



Minimum * " — 18 270 — 

69 % of coef. of crippling. 
Variation of min. from average = 18 % 



Phcenix. 



110 18 880 

110 I 23 170 

112 18 960 

112 I 28 420 



Average value of /i, = 22 366 lbs. 
Minimum " " = 18 880 " — 

6i % of/ Ihe coef. of crippling. 
Variation of min. from average =18% 



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84 



AiiiiOwsD WoBEiNa Stbain. 

The determination of the allowed working strain per square inch of 
cross section is of vastly more interest for oonstruotiYe purposes than the 
breaking or crippling strength. 

The capacity of any material to resist repeated and continued load- 
ings, is dependent upon restricting the maximum strains within the 
elastic limits ; especially where the member forms part of a skeleton 
structure, in which the relative strains are entirely controlled by relative 
elongations and extensions of the several pieces. 

We are not justified, however, in loading our columns up, or near to 
the elastic limit, for the following reasons : 

Ist. Oar tests are merely statical tests with a limited number of 
loadings ; also, our calculations of strains are all statical; while the actual 
loads applied in practice and the strains induced from them are dynamic 
in action and repeated in application. 

2d. Columns beside being strained by direct loadings, are seldom 
exempt from the liability of being struck transversely/ by passing bodies. 

3d. There should be some allowance for possible defects in work- 
manship and material. 

It would therefore appear proper to limit the maximum allowed 
strain per square inch to within one-half of the least elastic limit of 
the columns. 

Believing that the reference of the so-called '• Factor of Safety " to 
the rupturing or crippling point is false in doctrine, and delusive in its 
effect, not only upon the general public, but, unfortunately, upon some 
of our own profession, the writer would suggest the greater correctness 
of considering the limit of elasticity as the proper point of reference. 
His own preference, however, is to determine as near as may be, the 
maximum strain to be allowed in each case for the required material, and 
then to specify the maximum allowed strain^ instead of depending upon 
a fictitious factor of safety. Instead, therefore, of computing the 
crippling strength of a column by the preceding formulse, and taking i, 
5 or } of this as the allowed strain, he prefers to change the formulaa so 
they will give directly the allowed strain. 

Taking 44 % (about the proportion used in tension members), of the 



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85 

minimnm Yalue of/i , from Table 7, -we get the following valaes for/2, the 
coefficient of allowed working strain : 

American Co. *s columns, /a = 6 930 
Box " "6 680 

Open " " 8 040 

Phoenix " ** 8 310 

That for American Co*s columns is too low comparativelj, for this 
minimum is from a pin ended column which gave a low value for rup- 
ture also, and the fault may have been due to a bad fitting of the pin. 
And as the general average for this class of columns is even higher than 
the average for the box columns, it would be proper to give the American 
Go.'s columns a highep figure than that derived from this exceptionally 
low minimum. Taking, therefore, the next higher value of/, we get for 
American Go's columns, /2 = 6 636. 

By introducing these values of /^ in the general equations c, d and e, 
or in (6), (7), (8) and (9), we obtain equations giving the safe strain upon 
the several kinds of columns under loads acting upon the extremities of 
the columns similarly to the manner of testing the columns in the testing 
machines. While columns proportioned by such formulse would be of 
equal strength comparatively for this kind of a loading ; they would not 
have equal resistance to forces acting transversely to the axes of the 
columns, and seldom would we be justified in neglecting a consideration 
of such transverse forces. 

The columns with the higher coefficients would, for same loading 
equal lengths be of a smaller diameter than those of the lower coefficients, 
and hence more liable to deflection by side blows. 

The longer diameters of each class of columns would also be of a de- 
creasing strength against such an application. 

Mr. C. Shaler Smith has partially provided for this difficulty by 
adopting an increasing factor of safety in the following manner : 

Factor of safety ^ 4 + -^jr^r H 

which gives the following values for this factor : 

IZ = 10 Factor of safety = 4.5 

20 " =6. 

30 '* =5.5 

40 " =6. 

50 " =6.6 

60 •« =7. 



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86 

Believing this redaction to be very desirable, we will adopt the 
principle and reduce onr values of /j in the same proportion, or as : 

1 ; 1 + 0.0125 H, 
and nearly as : 

1:1 + 0.033 R. 
This reduces our general formulsd c, d^ and e to the following form for 
allowed working strain : 



Square ends, ^= _^J___^(i^o.033 i?) 

^+"T8000" 



Pin ends, 



A 



" (ig-33)^ • ) (10) 

"^ 18 000 



Bound ends, "=-- — -^^^ 
1+ ^ 



18 000 



P I 

Where o =allo wed working strain per square inch, i2 = ^- = ratio of 

length to least i-adiua of gyration, /2 = coef. of working strain. 
For American Co/s columns, /2 = 6 600 
Box " " = 6 500 

Open •* " = 8 000 

Phoenix " '* = 8 300 

To obtain similar formulsa in terms of the ratio of length to diameter, or 
least dimensions, we make the same substitutions in FormulsB (6), (7), 
(8) and (9). 

For Phoenix columns : 



a . P 8 300 

Square ends, ^- = (i^rsof^^ (1+0.0125 H) 



Pin 



i< (t 



2400 
8300 



Bound •* '* =- ^ 

1 +_J?_ 
^ 2400 



^ (^12)^ • ) (11) 

"^^ 2400 
8 300 



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87 



For American Go.'s columns .■ 



Square ends, ^ = —^1^24? ^ ^^+^'^^^^ ^ 1 

^■^ Teoo" 

6 600 
Pin «« «« = 



(12) 



(F-10)^ 
^■^ 1600 



For box or square columns ; 

Square ends, :J = _^^2P - (^+^-^^^ ^ 1 
^■•■"3 000" 



Pin 



For open columns : 



6600 



(13) 



"l I (^-13)' 



3000 



Square ends, ^= 7:^0^ ^^ (l+^-^^^S ^J 

^■^ 2 475 

8 000 
Pin •« " = 



(14) 



1 . (^-12)_= 
"^ 2 475 



where J7 = -=- = ratio of length to least dimension. 

In Table 8 we give the values of the preceding formulae with and 
without the reducing factor (1 +0.0125 H) for the several columns, and 
also of Gordon's formula with a factor of i. 



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88 






I 

O 
P 



!§ 

« 

§ 



£ I 






QQ 
O 



O 



3 



1 ^ 

i 




1 

a 

1 


the valnes ob- 
tained by omit- 
ting the factor 


-1^ ^ 


i 
i 


• 

a 

1 




00 


8 337 ' 6 670 
8 000 6 818 
7 690 6 126 1 


4024 
3 352 
2 691 1 
2000 


1^ iH 


6 540 
6 867 
4 859 
4000 


1 § 


m 

1 

1 


A 




6 462 
4 736 
4243 


3 610 
2 946 
2340 
1838 


S 2 


m 


8 


6 828 
6 610 
6364 


6866 
6 163 
4 888 
3 676 


8064 
2660 


American Co.'s Colamns. 


A 


! 


6333 
4 700 
8800 


2866 
2064 
1616 
1116 


i § 


m 




6666 
6466 
6 700 


4640 
3646 
2 842 
2230 




1 

j 


A 


00 


6928 
6 037 
6 312 


4380 
3 460 
2666 
2 032 


eq eo 


4 


i 


§ 1 i 

00 00 t- 


7 115 
6 037 
4980 
4066 


1 g 


1 

Gordon's Form- 
ula. } lbs. per 
square inch. 


00 O CO 

i s s 

CO le <«i 


3928 

3 272 1 
2 734 
2300 


5 i 


si 


'i 

SO 


o 


^ ^ ^ 


g §•? s 


s 1 



Digitized by VjOOQIC 



89 



4H 

sill 



gi§li3§§§§ 



eo d c« ^ 



t«tOM»<«eOC4^iHf-l 



I 



I 



i 
I 



^ 

i 






I 






g 









lislSiisi 



to <« CO e« e^ 



i 



■5 « 



<0<DiO<#eOe«CI<HrHiH 



iii§§§§sig. 






ill 



§i§i§si»ii 



■<«< 00 es 



SS^$S8^SS8 



Digitized by VjOOQIC 



90 

The great difference in the bending effect shown bj the factors 1 600 
to 3 000 as derived from the moments of inertia of the columns ; and as 
is shown in the tabulated figures ; illustrates the economy of massing 
the metal far from the axis of the columns, as is done in the Phoenix, Box 
and open columns. 

These fig^es, however, do not show the relative economy of the col- 
umns, for in the box and open columns there is a greater freedom in 
selecting the diameters, without increasing the areas proportionately, 
than in the Phoanix or Amer. Co.'s style of columns. Other factors, as 
the price of the material and facility of forming connections, also enter 
into the problem. We regret that Mr. Howard should have gone out- 
side of the record, in his report upon Phoenix columns, to make the fol- 
lowing remark: * * * *• Therein they differ materially from 
lattice columns. The latter form (lattice columns), after deflecting 
slightly, suddenly give way by tearing out the riveting of the ^ttice 
bars, after which but little strength, as a column, remains.*' We fail to 
find any such action recorded in Mr. Bouscaren's experiments, and are 
not aware of any experiments upon well made and well proportioned lat- 
tice columns that would justify such a remark. Mr. Howard's position 
should make him cautious, to prevent his interest in a series of experi- 
ments from drawing him into any appearance of bias or partisanship. 

Phoenix columns can well stand upon their excellent record and recog- 
nized merits. 

CoNOLuaioN. — ^After a careful consideration of the experiments we* 
possess, it becomes very clear that we cannot allow Gordon's formula to 
be our standard of strength for all forms and kinds of columns. Neither 
does Bankine's formula represent correctly the results of our tests. 

Those given by the writer are submitted for the consideration of the 
profession. 

But, whatever formula we may adopt, it has been made dear by the 
experiments of both Hodgkinson and Bouscaren, that the strength of 
wrought-iron columns are not only dependent upon the ratios of leng^ 
to diameters, and the shape of the cross section ; but also to a very great 
extent upon the proportions of parts, details of design and workmanship, 
and the material from which the columns are made. So that it becomes 
as necessary in our specifications to detail carefully the kind of material, 
proportions of parts, and character of workmanship, as to specify the 
formula to be used in estimating the sectional areas. 



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HYDRA 




^ Digitized by 



GooqIc 



I 



JM 













PLATK I. 
TRANS AM SOC CIV. KNGFt's 

VOL. XI. N" rrxxxni. 

COOPRR 
OK WKOUGHT IRON COLUMNfi, 



JMNS 



z/%furiavuits 



"7^ 




wo 



770 



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w: 



'^ 



'linitiyoH h\/ 



mk 



( ^poaTp 



PLATE U. 

TRANS AM. SOC. CIV. ENGRS 

VOL.XI.N^CCXXXIll. 

COOPKR 

ON WROUGHT IKON COLUMNS 



Columns 



\0/tj:=zR 



vcr. 




600 3J0 320 330 3^0 



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91 
Discussion by D. J. Whittemobb, M. A. S. C. E. 

I yeninie to say that if one versed in making tests of bnilding ma- 
terials shonld be asked to state how many tests of like kinds shonld be 
made, £rom which to determine a fair average, he wonld say at least four, 
probably six. In my experience, tests of compressive strength of all 
kinds of material nsed in construction are subject to nearly donble the 
variation f onnd in tensile tests of the same material ; therefore, when 
we have, as in the present case, twenty tests, being only two to each 
different length of column, and the resulting tests on each length having 
a variation from the mean, in one instance only, of five per cent. ; in 
three other instances from one and one- half to two per cent., and in 
the balance the traction of one per cent., we may well express our sur* 
prise and admiration at the tu^ormity attained. These tests were made, 
however, through the agency of probably the best testing machine of its 
capacity ever coDstructed, and the results, in view of the facts above 
recited, should and will command the attention of every intelligent 
engineer. 

It is true that Gordon's formula does not express the true strength of 
these columns, as asserted by the authors, neither can it be made to do 
so by any change in the value of its factors. It is also, I believe, repug* 
nant to our understanding to admit that two formulae will be required 
to express strength, when the facts are approximately known. The line 
of rapid descent in streogth appears to have been reached at 16 diame- 
ters, and at about the point where the ratio between the thickness of plates 
and distance apart of rivets equals the diameter of the column into its 
length. The two tests at this point show uniformity of strength, but it 
may be remarked thatone'of these columns buckled by shearing of rivets, 
and this was the only instance of the kind, and that the elastic limit of 
the other was much below any of the others recorded. Is it in reason to 
suppose a column 15 diameters long to be no stronger, or not even as 
strong, as one of 18 or 24 diameters in length ? 

Had there been a variation of results in these columns as great 
as was found in the tests of the columns 10^ diameters long, giving 
an increased mean value to the same, the results would not appear so 
anomalous, as they now <!ertainly do. All experiments are immensely 
suggestive of further tests, and the only conclusive solution that I can 
think of would be to test at least four more similar specimens of 16 



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92 

diameters in length. It also occnrs to me that the strength value of 
posts of the size tested might be very materially increased between 9 
and 36 diameters in length by riveting the segments together after some 
snch mle as the following, i, e., distance apart of rivets in inches shall 
not exceed the square root of the length of the colamn as measured by 
its diameter. 

Undonbtedly the laws governing force and matter can be expressed by 
formulfldy and as an indication that the case in hand is not an exception, 
from several formalae I have devised, I select the following as an ex- 
pression of the probable ultimate strength of these columns, as indi- 
cated by the experiments cited, i. e, : 

^=(1200-//) 30 + 5?^ 

Where i7i=^^^e — 
O utsidVi^nieter 

Evidently this formula will not apply to columns longer than 45 or 

shorter than about 5 diameters in length, but it will be observed that 

covering the tests mentioned by the authors, the average variation from 

all tests does not exceed one per cent., though in the one instance, that 

at 15 diameters the variation amounts to four per cent. In the following 

table I have entered in the column of actual strength the average of the 

two tests on each length of post, and also the single tests on eleven-inch 

columns of 9 and 25} diameters : 



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93 



H. 


ActuM Streo^h per Square 
Inch, by Experiment, 

50 370 




By Formula. 
200-^)80 + ^^7^ 


6 


50400 


9 


42180 




42 224 


m 


40 728 




40 447 


15 


36 438 




37 883 


m 


37 028 




36 796 


24 


36580 




36191 


25J 


36 010 




36 043 


28^ 


36132 




35 791 


33 


34965 ' 




35 492 


37i 


35155 




35 248 


42 


34650 




35 038 



^= ^ : as given by the aathors of the paper in the colnnm headed, 
'* Batio of Diameter to Length.*' 

DiBOussioM BT Chablbs £. Ehebt, M. a. S. C. E. 

I have taken great interest in this valuable paper, and trust that the 
example set by this well known firm may be followed by others who 
have occasion to use the Government Testing Machine, as various ex- 
periments, carefully analyzed and discussed here, will be the means 
of greatly extending the information of engineers on this important 
subject. 

It has probably been the impression of many here present that hereto- 
fore each writer, in discussing experiments on this subject, has con- 
structed a formula with an ample factor of safety, to which compilers 
have added an additional factor of safety to cover exceptional cases, and 
that this process has been continued until the formula no longer repre- 
sents the actual facts, but give results unnecessarily safe when good 



Digitized by VjOOQIC 



94 

workmanship and material and symmetrical sections of approved form 
are provided. 

This state of facts has undoubtedly been caused, to a great extent at 
least, by the differences in result obtained in different experimei^ts, par- 
ticularly with columns made of cast-iron of different grades, and con- 
structed without special pains to secure uniform thickness and freedom 
from defect. 

Engineers have for a long time felt that the segmental circular 
columns of Clarke, Beeves & Co., were far more reliable than those upon 
which the greater part of our literature on the subject is based, and the 



^^00 




piArvneTeA.& IN LEMC 



thorough tests herewith presented in addition to those heretofore pub- 
lished, show that the opinion is well founded. 



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95 

The diagram presented with the paper indicates dearly that two for- 
mnlsB are needed to represent the experimental onrve aconrately, as has 
been pointed out preyionsly by many writers on the general snbject 
in relation to other experiments. 

In examining these experiments for the purpose of developing a 
simple formula for my note-book, I find that the whole of the experi- 
mental curve can be represented approximately by one formula which 
will be very accurate within the limits where formulae are generally used, 
and not vary seriously for shorter lengths. The curve is a hyperbola, 
with the equation : 

855 063 -I- 30 950 a; , ^ 



•^ a? 4- ($.175 

in which y represents the breaking load in pounds per square inch, as 
shown by the ordinates in the diagram ; and x, the number of diameters 
in length, as shown by the abscissa of diagram. 

The curve developed by this equation has been plotted on one of the 
printed diagrams presented by the writers of the paper, and a copy of 
the same is herewith reproduced. It will be seen that the curve is very 
accurate from twenty diameters upward, and corresponds with the ex- 
perimental curve better in form and position than that given by Gordon's 
formulffi, as plotted by the writers of the paper. At 15 diameters the 
results given by the formula are higher than the experimental ones, but 
for a less number of diameters the experimental results are the higher, 
making the formula as a whole perfectly safe, as the slight variations 
will be provided for in the factor of safety. 

Discussion by Db Volson Wood, M. A. S. C. E. 

Engineers are naturally interested in these experiments, not only on 
account of the information which they will gain in regard to the resisting 
properties of the Phoenixville column, but also because the results de- 
termined are more reliable since the tests were made with the most ac- 
curate testing machine the world has ever known. It is a matter of pride 
that this country possesses the only machine with which the actual 
stresses, even though they amount to hundreds of tons, may be deter- 
mined within the fraction of a pound. 

In regard to the results of these experiments, it is remarkable that 
the law of strength appears to change so suddenly with columns of 15 



Digitized by VjOOQIC 



96 

diameters, the valne originally indicated by Hodgkinson. For larger 
oolnmnH the law seems to be approximately, but not rigidly, represented 
by Gordon's formula. The line representing the computations by Gor- 
don's formula seems to drop more rapidly than the line representing the 
results of the actual experiments, and for this reason Gordon's formula 
may need a correction in order to represent these experiments more ac- 
curately. But I do not understand why the line representing Gordon's 
formula should be so far below the other. The constants in his formula 
should be determined by means of these experiments and not from the 
results of English experiments, since the form of colunm and the material 
are both different. Had this been done the curve would have nearly co- 
incided with some portion of the experimental curve. The formula may 
be written. 

P (streugth in pounds) = ^ (constant) x.^ (area in sq. in.) 



1+ (7 (constant) Xr2 f square of") 
the ratio of i 
length to 
radius of 
gyration. 

It is sometimes stated that B in this formula is the resistance to ulti- 
mate crushing. This would be the case if the law of resistance were true 
without limit ; for when / = o, we have F = B A, But the law cannot 
be safely extended much, if any, beyond the limits of the experiments. 
The true way to find the constants is to substitute known contemporane- 
ous values for P, Ay and r, thus forming as many equations as there are 
experiments, any two of which will give definite values for B and C. If 
the formula represents the law of strength with sufficient accuracy, the 
mean values of these constants, as determined by different combinations 
of the equations above formed, will be the proper values to be used in 
the formula. If the law changes at 15 diameters, or at any other point, 
the formula should not be distorted so as to take in the whole range of 
the experiments. Another formula should then be used for lengths less 
than 15 diameters.- I regret that I have not been able to give the time 
necessary to enable me to carry out these numerical computations, and 
to give to the whole subject a more critical study. 

I desire to make a remark upon the report of the examiner. I observe 
that the sets which were observed after the stress was removed are gen- 
erally recorded, while in a majority of cases the total compressions are 
omitted. The experimenter has indicated the limit of elasticity in several 



Digitized by VjOOQIC 



97 

cases, bnt so far as the record shows, these limits are arbitrary. A com- 
plete set of all quantities observed should be recorded to enable an j reader 
to judge for himself of the accuracy of the work, and the correctness of 
the conclusions, as well as to permit of more accurate comparison with 
other experiments. 

Discussion bt Chables £. Emebt, M. A. S. C. £. 

Ih BEPL7 TO Pbofbssob Wood. — We are all very much interested in 
Prof essor Wood's clear discussions of scientific subjects, but I must con- 
fess that I cannot agree with him that Gk)rdon*s formula even approx- 
imately represents the curve shown by the experiments under discussion. 
The variation is not that simply due to a lower position on the diagram, 
but within the limits mentioned, Gordon's formula gives a curve con- 
cave to the axis of abscissas, while the experimental curve is evidently 
convex to such axis. This is an important difference, for it is evident 
that an equation of a straight line would more accurately represent the 
experimental curve than the curve given by Gordon's formulsd between 
the limits shown. In fact, the experiments are very well represented by 
two straight lines with the following simple equations, viz. : 

First— 

y = 39 220 — 118 x (b) 

which is very accurate between the limits, 12 to 40 diameters, safe for a 
less number of diameters, and probably also for a greater number within 
reasonable limits. 
Second. — 

y = 57 500 - 1 642 a: (c) 

which is approximately accurate between the limits to 12 diameters, 
the notation being the same as before . 



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•98 



Discussion by C. L. Stbobel, M. A. S. 0. E. 

The interesting series of tests on Phoenix colanms instituted by 
Messrs. Clarke, Beeves & Co., deserve careful study, as throi^ing addi- 
tional light upon an important engineering subject, still much involved 
in obscurity. I think, however, that their reference to Gordon's formula 
implies a misapplication of the same, and gives an improper interpreta- 
tion to Hodgkinson's tests from which the constants in the formula were 
deduced ; and I shall attempt to show that these tests on Phoenix columns 
do not conflict with the latter, but, on the contrary, serve to strengthen 
and confirm the conclusions to which they have led. 

Of the 22 Phoenix columns tested, 20 are four-segment columns of 8.04 
inches diameter from out to out of cylindrical portion. The areas of 
these 20 columns are practically the same, the average being 12.122 square 
inches ; the diameter is given at 11.5 inches from out to out of flanges. 
Calculating the thickness of metal from these data, we obtain 0.32 inch 
for the thickness of the cylindrical portion and 0.31 inch for the mean 
thickness of the flanges, whence the moment of inertia is found to be = 
109.72, and the square of the radius of gyration = 9.05. 

The general form of Gordon's formula, applicable to any cross section, 
is the following : 

p f 



S~ l+a^ (1) 



r 



In this formula P represents the total pressure under which the 

P 
column fails, ^S^ its sectional area, and consequently —7 its ultimate 

strength per square inch ; / is a constant dependent upon the form of sec- 
tion and the ultimate strength of the material ; a is a constant also depend- 
ent upon the form of section and the ultimate strength of the material, 
but also dependent upon its elasticity, being inversely proportional to 
the modulus; /= the length of column; r = the radius of gyration of 
the section. The constants/ and a are determined by experiment. 

Applying the above formula to a hollow cylinder or tube, and letting 
d represent the diameter of an equivalent circle whose radius of gyration. 



Digitized by VjOOQIC 



99 

Msuming the area concentrated in the ciroomrerenoe, is equal to that of 
the section of the tube, we have, for this form of cross section, 
P_ f_ : 

Since r^=-— 

o 

Again, applying the general formola to a colamn of solid rectangular 
section whose least side = h^ we have, 
P f 






Since r* = -~ 
1^ 



The general form (1) of the formula has sometimes been called Ban- 
kine*8, while the special forms (2) and (3) which the former assumes by sub- 
stituting for r' its equivalent in terms oi d} oth}, has been designated 
Gordon's. I have not thought it proper to preserve this distinction, and 
there is, of course, no difference in the results obtained from either, pro- 
vided that, in applying the special forms (2) and (3), the proper ** equiva- 
lent " diameter or least side is first obtained from the equation d = v^8 . r ^ 
orA= /l2:r^ 

Our main reliance for the determination of the constants / and a, has 
been, to the present time, the tests made by Hodgkinson about 35 years 
ago, preparatory to the building of the Britannia and Conway tubular 
bridges. Of his tests on wrought iron, those on bars of solid rectangular 
section are best suited for the determination of the constants, because 
their range is greatest and the form of section may be best relied upon to 
give results least affected by accidental irregularities due to shortcomings 
in the manufacture. To these tests Gordon applied his formula in the 
form No. 3, and found that if / was made = 36 000 and 12 a = 3 000, 
(units being the pound and the inch), the results of the tests would 
best conform to the values given by the formula. If we may assume, 
now, that the constants which apply to one form of cross section, will 
also hold good for other forms, we obtain from (1) the following general 
formula for square bearing wrought-iron columns : 
i>^ 36000 



W 



Digitized by VjOOQ IC 



100 

We shall see, presently, whether the experiments justify this assnmp- 
tion. 

It is well known that short columns do not fail by flexure, but by the 
buckling or bulging of the metal, and that the strength of such columns 
is measured by the strength of short portions to resist this tendency, and 
is independent of their length. Gordon's formula assumes that flexure 
takes place, and that the direct compressive strain (which is uniform in 
a column which does not deflect from a straight line), is augmented by a 
bending strain. It is therefore a question to be determined by experi- 
ment, when is the ultimate strength of a column independent of its 
length and when does Gordon's formula apply. Hodgkinson's experi- 
ments on rectangular bars shed no light upon this question because tests 
on bars between 18 and 36 diameters long are lacking, but they indicate 
that bars 36 diameters long belong to the class of columns which fail by 
flexure and to which therefore the formula is applicable. His tests on 
rectangular tubes are more seryiceable in this respect, though they are 
limited in range, none of them exceeding in length 30 times the least 
breadth, equivalent to 26 diameters if the diameter of the cylindrical tube 
be adopted as unity. Referring to these tests Stoney draws the following 
conclusion : " When the length of a rectangular wrought iron tubular 
pillar does not exceed 30 times its least breadth, it faHa by the bulging or 
buckling of a short portion of the plates, not by flexure of the pillar as a 
whole, and within this limit the strong^ of the tube seems nearly inde- 
pendent of its length. It is quite possible that the ratio of length to 
breadth of wrought iron tubes might be considerably greater than 30 
without very materially affecting their strength, but the recorded experi- 
ments do not extend sufficiently far to determine this point." It was 
found that the crushing unit strain was dependent upon the ratio be- 
tween thickness of plate and breadth of tube, being generally greater 
the thicker the plate, and the general rule was deduced that the thick- 
ness of plate should not be less than one- thirtieth of the breadth of tube 
or distance between supports. The average ultimate strength of the 
rectangular tubes which conformed to this rule was 27 000 pounds per 
square inch. 

Besides the tests on bars and tubes of rectangular section, Hodgkin- 
son made a series of 37 tests on cylindrical tubes, ranging to 85 diame- 
ters in length. Qomparing the results between 14 and 23 diameters, the 
differences in the ultimate strength are very small, but bet^veen 23 and 32 



Digitized by VjOOQIC 



101 

diameters there is much irregularity, and the evidence is not conclosiye 
that within these limits the ultimate strength is independent of the 
length. If the best results only are considered, this is the case, even a 
tube 42.9 diameters long showing an ultimate strength but slightly less 
than the average. I am inclined to think that much of the irregularity 
in the results is due to imperfections in the manufacture of these tubes, of 
most of which it is stated that they were united by '' soldering or other- 
wise." Five of them were formed by bending a plate into the form of a 
cylinder and making a lap joint along which a single line of rivets was 
driven, and these tubes invariably gave higher results than the others. 

Averaging the results of the tests on lengths between 14 and 32 diam- 
eters, we obtain 33 100 lbs. as the ultimate strength per square inch of 
cylindrical tubes, whence it follows that this form of cross-section is 
much stronger than the rectangular tubular. This being the case for 
lengths up to 32 diameters, it is also probably true of lengths exceeding 
32 diameters, and comprehensive tests on different forms of cross-section 
would no doubt show that different constants are required in Ck>rdon's 
formula for each. The formula in the form (4) cannot therefore be con- 
sidered as giving correct results for all forms of cross- section, though, in 
the absence of such tests, it has been necessary to use it without limita- 
tion. Applying the formula to the cylindrical tubes tested which exceeded 
32 diameters in length, the calculated results are found to agree fairly 
well with the results by experiment, the latter being even generally 
higher than the former. This appears strange at first glance, since it 
would then follow that a solid rectangular column is no stronger than a 
cylindrical tube, although the former has the advantage of holding its 
material better together, making wrinkling or buckling impossible. But 
an explanation is easily found in the circumstance that the width of base 
of the rectangular column is smaller than that of the cylindrical tube in 
the ratio of 8 to 10, nearly, and that the rectangular column has conse- 
quently less fixity of ends than the other. In fact, strictly speakiug, 
columns without discs cannot be considered as *' fixed" at the ends, 
since, being made of elastic material, these will necessarily yield some- 
what to a pressure which tends to bend the column ; and when it is con- 
sidered that a column with round ends is, as regards flexure, the equiva- 
lent of a square bearing column of twice its length, the importance of 
fixity at ends is evident. 

In view of the importance and value of Hodgkinson*s tests, even to 



Digitized by VjOOQIC 



102 

the present day, inasmuch as they still form our main guide in the pro- 
portioning of members subjected to compression, and for the reason 
that, so far as I know, they have not heretofore been published in con- 
venient form for reference and comparison, I have prepared a tabular 
statement of his tests on the compressive strength of bars and cylin- 
'drical tubes, showing in adjoining columns the ultimate strength per 
square inch by experiment and by calculation. Gordon's formula in 
the form (2) was used, in which the length is expressed in terms of the 
diameter of a tube, in order to facilitate comparison with the Phoenix 
tests. In every case, however, the proper *• equivalent " diameter was 
calculated from the radius of gyration, so that formula (4) would give 
exactly the same results. 

The tests were made in a lever testing machine, the specimens being 
placed vertically between square bearing surfaces with ends carefully 
bedded. The data for the tables were obtained from Edwin Clark's work 
on the Britannia and Conway Tubular Bridges. Some small discrep- 
ancies occur in the thickness given for the tubes, as compared with the 
outside and inside diameters, but they were unexplained in the origincd, 
and could not be corrected. 

Beverting now to the tests on Phoenix columns, it is necessary tocor- 

p 

rect, first, the graphic representation given of the values of -o- obtained 

by Gordon's formula ; by some oversight the values plotted are those for 
solid rectangular sections. Next, it is obvious that the inside diameter 
of Phoenix columns is not the proper diameter to use in the formula, 
and that, therefore, the ratio of length to diameter needs revision. For 
the 8 inch columns r^ was found = 9.05, whence the equivalent diameter 

is obtained as V8r^ =8.51 inches. Therefore,— for the 28 feet col- 

a 

umns, experiments 1 and 2, becomes 39.5 instead of 42, and for the 10 
feet columns, experiments 13 and 14, 14.1 instead of 15. Comparing 
experiments 1 to 14, inclusive, with each other, the slight variation in 
the ultimate strength per square inch is very striking. The average is 
found to be 35*800 lbs., and the greatest variation is only 1 400 lbs. (for 
experiment No. 2), while the range is from 14.1 to 39.5 diameters. Of 
the Phoenix experiments it may therefore be said that they furnish better 
evidence than Hodgkinson's own tests for the conclusion to which these 
have led, viz., that the ultimate strength of tubular columns not over 26 



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Hodgkinson's 



30 


6.125 


28.3 


4.026 


! 
28.3 


4 


60 1 


6.176 


28.26 1 


3 


30 


2.49 


29.1 


2.373 


29.1 


2.343 


29.9 


2.383 


29.9 


2.343 


30 


2.34 


30 


2.335 


90 


6.366 


60 


3.995 


60 


3.996 


30 


1.964 


120 


6.366 


120 


6.187 


30 


1.495 


90 


4.052 


89.3 ' 

1 


4 


89.3 


4 


89.3 1 


4 


60 


2.49 


60 


2.36 


60 


2.335 


119.25 


4.05 


119.25 


4.06 


90 ! 


3.035 


60 


1.964 


119.25 1 


2.995 


eo 


1.495 


119 , 


2.49 


120 


2.34 


120 1 


2.35 


119 


1.964 


119 1 


1.495 



"a 

I 

s 



I 



I 
I 

! 



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Digitized byCjOOQlC 



Digitized by VjOOQIC 



103 



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Digitized by VjOOQIC 



104 

diameters long is independent of their length ; and while these tests 
made it appear probable that this limit might be extended, the Phoenix 
tests fnmish proof that lengths of even 39.5 diameters should be in- 
cluded. All of the Phoenix columns tested belong, in this light, to the 
class which does not fail by the flexure of the column as a whole, and to 
which Gordon's formula does not apply. Thej are, therefore, not avail- 
able for the purpose of determining the constants in the formula, and 
no comparison with the results given by the formula is proper. 

The relative strength of Phoenix columns within the limits mentioned, 
compared with Hodgkinson's cylindrical and rectangular tubes, would 
be as 35 800 : 33 100 : 27 000. We have no means of knowing whether 
Phoenix iron of the present day is better or less qualified to resist com- 
pressive strain than the iron used in Hodgkinson's tubes 35 years ago, 
but it would certainly appear reasonable to assume that a part, if not all, 
of the gain of 2 700 lbs. over the cylindrical tubes is to be attributed to 
the better form of cross-section of the Phoenix column. The flanges 
strengthen the cylindrical portion of the column, resisting deformation 
in a diametrical direction, while any tendency they may have to deflect 
sideways, in which direction they are weakest, 'will be resisted by the 
cylindrical portion in the direction in which it is strongest. Some benefit 
will also accrue to the Phoenix columns, probably, through their larger 
base, the projecting flanges acting somewhat in the manner of discs. 

So far as the tests on Phoenix columns of less than 14 diameters 
length are concerned, the results do not differ materially from those ob- 
tained by Hodgkinson ; like them, they show an irregular and sometimes 
considerable increase of strength ; and the very short lengths simply 
illustrate the well known fact that if a ductile material is held in place so 
that it cannot readily get away, it will bear a largely increased com- 
pressive strain. 

The results of the Phoenix tests are not directly applicable to the 
posts of bridge trusses, because these are not in the condition of the 
columns in the testing machine. Where Phoenix columns are used for 
vertical posts in bridge trusses, the lower ends, generally through the 
interposition of a foot casting, are pin-bearing, a condition intermediate 
between a square and a rounded (spherical) bearing, while the upper 
ends of the columns abut against the underside of a cast joint box, also 
not the equivalent of the bearing surfaces of the testing machine as re- 
gards fixity laterally. It would seem probable, however, that columns 



Digitized by VjOOQIC 



105 

which are pin-bearing at both ends have a aniform ultimate strength 
irrespective of their length to 23 diameters, and that the ultimate 
strength for Phoenix columns will average 35 800 lbs. within this limit. 

The first tests on columns under conditions corresponding to those 
which prevail in bridges of the American type, viz,, pin-bearing at both 
ends, were made by Mr. Bouscaren for the Cincinnati Southern Bailway, 
and published in the report of its then Chief-Engineer, Mr. T. D. 
Lovett, in 1875. They have been of great practical service as furnish- 
ing the means of at least approximately determining the constants in 
Gordon's formula for columns of this class, but additional experiments 
are much needed. The tests on square-bearing columns made by Mr. 
Bouscaren and published with the above in the December number of the 
Transactions of 1880, are mostly on lengths under 30 diameters and cannot 
he used for the determination of the constants for the different classes of 
columns experimented with, but they furnish additional proof of the 
correctness of the conclusion that tubular columns not over, say, 39 
diameters long, have a uniform ultimate strength per square inch inde- 
pendent of the length. The following exhibit will make this very clear, 
in which the numbers of the experiments correspond to the numbers in 
the tables accompanying Mr. Bouscaren's paper, and the ** equivalent " 
diameters again refer to diameters of cylindrical tubes, and are calculated 
from the radius of gyration. 

Columns 38, 41 and 42, the iron for which was rolled by the same mill 
at about the same time, and which were built at the same works and 
tested in the same machine, show, it may be said, exactly the same ultimate 
strength x>er square inch for lengths of 21.4, 25.6 and 31.8 diameters. 
From these tests we may infer that the strength of columns made of two 
channels latticed, is at least 32 300 lbs. per square inch, as compared 
with the averages given above for the Phoenix and the Hodgkinson 
columns. 

Experiment No. 37 requires explanation. Mr. Bouscaren attributes 
the low result which this column gave to the small thickness of webs of 
ohanneb, which was a little less than a^th of the distance between in- 
side of flanges. But the webs in column No. 38 are no thicker, this 
column being, in fact, a duplicate of No. 37, except that the flanges of 
the channels are somewhat heavier, yet No. 38 stood fully as well as 
columns 41 and 42, which have heavy webs. Though these channels 
are all rolled by the same mill, there is a marked difference in the mode 



Digitized by VjOOQIC 



106 



SijiiABB-BBA.BiNa CoLuuNs— G. Bodsoa.bsn's Ezpebiubnts. 



No. 


L«ngth. 


Eqaivalent 
Diameter. 


Ratio of 

Length 

to 

Eqaivalent 

Diameter. 


Ultimate 
Strength 

per 

Sqaare 

Inch. 


Kind of Ck>lumn and Remarks. 




Feet. 


Inches. 




Poands. 




33 


24. 


9.64 


29.9 


33 200 


Closed colamn. 2 8-inch channels 
and 2 lO-lDch plates. Iron from 
diiferent mUl than for other tests. 


S2 


27. 


9.84 


84.7 


80 200 


Closed column like above, but plates 
10.5 inches. 


1X2 


26. 


8.65 


36.1 


80 000 


Closed colamn like No. 28, but chan- 
nels 7 incbee. 


87 


27.47 


12.64 


26.1 


29 600 


Open colamn. 2 12-inch " plate " 
channels latticed 6-16th. web. 


88 


23.01 


12.87 


21.6 


32 300 


2 12-inch channels latticed, 5-16th.web. 


41 


27.6 


12.90 


25.6 


32 400 


2 12-inch channels latticed, heavier' 
web. 


42 


27.6 


10.37 


81.8 


32 300 


2 lO-inch channels latticed. 


40 


1.61 


2.366 


8.2 


35 700 


1 12-inch channel. 5'l6tb. web. 


89 


2.00 




10.1 


35 400 


Same as above. 



of mannfacture. Nos. 38, 41 and 42 were rolled from a regular channel 
pile in the nsual manner, while No. 37 (Union Iron Mills, Shape No. 26), 
is made by bending a plate to the form of a channel in the last two 
passes through the rolls. The channel produced by this process is infe- 
rior in strength and shape to the others, and this is, I think, the true 
explanation of the low strength developed by the column. Hodgkinson's 
rectangular tubes were composed of plates similarly bent, no channels or 
angle irons as now made by the mills entering into their construction, 
and they also gave lower results than appears attributable to their form 
only. 

Mr. Bouscaren, in his paper above alluded to, infers from the results 
of his experiments, that ** iron of the highest modulus does not neces- 
sarily make the strongest column,'* presupposing, of course, the other 
conditions to remain the same ; and in the comparisons I have made, 
dififerences in the quality of the iron as expressed by the modulus of elas- 
ticity and the ultimate compressive strength of the material, were not 



Digitized by VjOOQIC 



107 

alluded to. The latter is an indeterminable valne for a dnctile material 
like wrongbt-iron, and the former is seldom measured with sufficient 
aocuraoy to be of sernce. But both modulus and. strength are not very 
variable quantities for wrought-iron, and I do not think that, had they 
been properly considered for the above tests, the results obtained would 
have been materially modified. Mr. Bouscaren^s inference will not har- 
monize with the theoretic basis of Gordon's formula, and is supported 
only by the fact that the dosed rectangular columns tested by him, 
while giving a lower ultimate strength, showed a higher modulus than 
the Phoenix columns . But this result, as we have seen, was to be ex- 
pected as the effect of the different forms of cross-section irrespective of 
the modulus, and the conclusion, therefore, does not seem to be well 
founded. If his experiments on Phoenix columns be alone considered, it 
is true that the highest modulus corresponds to the lowest ultimate 
strength, but, per contra, nearly the same modulus (difference only 300- 
000) in another test gave the highest ultimate strength. 

In accordance with theory, the greater the modulus and consequently 
the stiffer the column, the smaller will be the bending moment which 
it will have to resist, and the greater its ultimate strength. Future ex- 
periments may show that the variations in the modulus are of sufficient 
influence upon the (strength of long columns as to require special con- 
sideration even for wrought iron, but there can be no doubt that the 
range of these variations is so great for steel, that no compression for- 
mula for this material can be considered complete which does not either 
limit its application to steel of a certain modulus, as well as ultimate 
strength, or in which the constant in the denominator is not a function 
of both. Very mild steel has a modulus probably smaller than that of 
ordinary wrought-iron, and, although its ultimate strength is greater, it 
is questionable whether it will sustain more or as much as the latter in 
the form of long columns. Again, if the modulus is the same, while the 
ultimate strength of the steel is to that of the iron, say, as 8 to 5, the 
strength of the steel column will bear some lower ratio to that of the iron 
column, because the higher pressure which the former sustains will pro- 
duce a greater deflection from the straight line, and the bending moment 
will therefore be increased not only in proportion to the greater force, 
but also in proportion to the greater leverage. While the saving in ma- 
terial for tension members is directly proportional to the greater strength 



Digitized by VjOOQIC 



108 

of the material employed, the saving for long compression members will 
be a different and smaller ratio. 

The following two tests, not heretofore published, are presented in 
illustration of this principle, showing the amount to which the increased 
strength of the material is counteracted by the absence of a proportionate 
increase in the modulus. The tests were made on two columnx, one of 
steel and the other of iron, both of 19 feet length between centres of 
pins, and 20 feet long out to out, and of the following sections : 



OfP/N 




r^ = 7.6 

Equivalent diameter ==7.8 inches. 

d 



29.2 



Both the steel and the iron were rolled and the columns built by Andrew 
Kloman, deceased, at the Superior Mills in Pittsburgh. They were tested 
horizontally in the Keystone Bridge Co. 's testing machine, in the position 
corresponding with sketch, counterweighted at the centre by a load equal 
to one-half the weight of the column. The steel was made by the Besse- 



Digitized by VjOOQIC 



109 

mer process, under the Hay patent, and was furnished under specifica- 
tions requiring an ultimate tensile strength of 80 000 pounds^er square 
inch. The column was one of a lot built for a steel bridge in 1878. Un- 
fortunately, measurements of the contraction under strain were not 
taken, and the modulus cannot, therefore, be given. The sectional area 
was 14.8 square inches for the steel, and 13.2 square inches for the iron 
column, obtained from the weight The dimensions g^yen in sketch 
correspond more nearly to the area of the steel than to that of the iron 
column. The pins were di inches in diameter. Both columns failed by 
deflecting downward. The ultimate strength attained in the case of the 
steel column was 30 900 pounds per square inch ; and in the case of the 
iron column, 24 800 pounds per square inch. While, therefore, the ul- 
timate strength of the steel may be said to haye been 1.60 times greater 
than that of the iron, the strength of the steel column was only 1.25 timea 
greater than that of the iron column. 

In Mr. Howard's report on the Phoenix experiments, he states that the 
Phoenix columns show a superior sustaining power after taking a deflec- 
tion of several inches, and therein differ materially from lattice columns,, 
which, after deflecting slightly, suddenly give way by tearing out the 
lattice bars. I understand that this behavior was observed on one lot of 
lattice columns only, and Mr. Howard informs me that similar columns- 
tested later, and obtained from a dififerent manufacturer, did not fail in 
this manner. Of- the lattice columns tested by Mr. Bouscaren, and of 
other columns tested at the works of the Keystone Bridge Co., none^ 
have failed at the rivets of the lattice bars, so that the behavior described 
cannot be said to be general for lattice columns, but must be confined 
to the particular lot of columns first tested, and is to be attributed, no 
doubt, to defective Aanci-riveting. 

In the foregoing remarks the ultimate compressive strength of the- 
material has been referred to, though it was stated that its value cannot^ 
be definitely ascertained. In consequence of this difficulty it has beeib 
customary to make tension tests on small specimens for iron and steel 
intended for compression in the same manner as tests are made on ten- 
sion material, on the assumption that material giving a high ultimate- 
strength in tension, would also give a high ultimate strength in compres- 
sion. 

Practically, the testing of material for quality must be done on small 
specimens cut from the large pieces. While it would not be impossible 



Digitized by VjOOQIC 



110 

to asoertain the modnluB in compression for these, it would be attended 
with mnch difficulty, and could not be done with our present testing 
machines. In place of the compression modulus it will, therefore, be 
advisable, also, to substitute the tension modulus, so that, generally, it 
may be said that it is necessary to judge of the compression qualities of 
the material by its behavior under tension. That being the case, I 
consider it very important that experiments on the compressive strength 
of compression members be always supplemented by tension tests on 
small specimens of the same material. This has not heretofore been 
done, and we therefore know nothing concerning the strength and 
other qualities of the iron used in former tests. It is particularly to be 
hoped that no experiments on steel columns wiU be made in future 
which are not accompanied by tension tests on small specimens and that 
special attention be given the modulus. 



DieoussioN BY A. S. C. Wurtelb, M. A. S. 0. B. 



On advance sheet sent me I wish to make the following remarks : 

The tables of experiments on Phoenix columns recorded in paper 
presented by Clarke, Beeves & Co., appear to be definite, as far as 
regards the strength of one particular column of about 12 inch section, 
but are unfortunately not sufficient to generalize on; and it is to be re- 
gretted, that the ends were not more carefully prepared and also that no 
tests were made showing the quality of the iron used in the columns. 

Without questioning the value of the Phoenix column, I would ask 
on what evidence the statement is made, that a lattice column gives away 
suddenly after a slight deflection ; which statement appears to me to be 
entirely irrelevant to the tenor of the paper. 

Bankine shows the theoretic deduction of Gordon's formula as an ap- 
proximation, but there is nothing to warrant the continued use of 
factors, known to be too small for good American iron, as displayed 
and spread on specifications for iron bridges. 

The thanks of the profession are due to Clarke, Beeves & Co. for giv- 
ing us the full tables in the paper ; which would be greatly increased in 
value if we could have similar tables for different sections and shapes. 



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Ill 

DiaoussiON BY Wn^iAM H. Bubb, Assoc. A. S. 0. E. 

While laboring nnder permanent ineligibility to membership by a 
somewhat anomalous rule of this Society, it is with the greatest hesita- 
tion that I venture to join in the discussion of this paper, which touches 
a subject at once interesting and important. The character of the sub- 
ject must therefore furnish the excuse for my presumption. 

At first sight (and the impression does not wear away by continued 
examination) it is a matter of no little conjecture to discover why Messrs. 
Clarke, Beeves & Go. should make a comparison of the Watertown experi- 
ments with the results of the application of the old form of Gordon's 
formula, which was designed and only intended for solid rectangular 
columns of wrought-iron of confessedly less ultimate compressive re- 
sistance than that of the present American production. It scarcely seems 
possible that a deliberate neglect of the influence of the form of cross- 
aeotion and quality of the material was intended, yet such an inference 
would be legitimate. 

It is not difficult to find a form of Gordon's formula (some may 
prefer to call it Tredgolds), which shall fit the whole range of experi- 
ments without great discordance, while with two forms of formula, as 
will presently be shown, very accurate results may be obtained. 

The form of Gordon's formula, to which reference was just made, is 
the following : 



42 000^ 1 + %(1 + JL)) 



^50000 r^ 
In which r = radius of gyration of cross-section in inches. 
I = length of column in inches, 

p = ultimate compressive resistance in pounds per square 
inches. 
log = Naperian or hyperbolic logarithm. 
In the following diagram I have represented graphically the results 
of the application of Eq. (1), and the experimental results given by the 
United States testing machine at Watertown. 



Digitized by VjOOQ IC 



112 




4-6000 



36000 



3-4000 



jaooo 



140 



The ourve indicated by ** Oordon^s Formula'* waa constmoted from 
Eq. (1) ; the other one was drawn so as to best fit the Watertown experi- 
ments. 

As a matter of interest, I have also plotted the results of the experi- 
ments bj Mr. Bonscaren, as well as those of some experiments made by 
the Phoenix Iron Co. at different times. The different classes of experi- 
ments are clearly indicated in the diagram. 

As is shown, the horizontal scale represents the quotients — , while 

r 

the vertical scale represents pounds. 

It is thus seen that the greatest discrepancy between £q. (1) and the 

experiments is not over 10 per cent. This, perhaps, is sufficiently dose 

for all ordinary purposes, yet more accurate formulse are desirable, and 

may be obtained. 

It is interesting and important to observe that each experimental 
value in the diagram (which, for the Watertown experiments, is a mean 
of two, belonging to columns of the same length), lies on, or exceed- 
ingly close to the curve, with the exception of those shown at a and b. 
a corresponds to a mean of Nos. 17 and 18 in the table (of the paper 
under discussion), and is abnormally high, b shows the mean of Nos. 
13 and 14, and is abnormally low. 

It may be remarked that the experimental curve is nearly a straight 
line from a point just above b to the extreme left of the diagram. For 



Digitized by VjOOQIC 



113 

that portion of the curve it will be found that the following formula ap- 
plies very closely : 

p' =39 640 — 46-^; (2) 

p' representing the ultimate resistance per square inch. The results of 
the application of this formula are given in the column headed p' in the 
following table. The table, in connection with the diagram, shows that 
this formula may be used with accuracy for values of l-^r, lying be- 
tween 30 and 140, and further experiments may possibly show that it is 
applicable above the latter limit. 

For values oi l-^r less than 30, the following formula will be found 
to give results approximating very closely to the experimental curve : 

p" = 64700— 4 60oV L; (3) 

The results of the application of this formula are g^ven in the col- 
umn headed p". 

The extreme simplicity of Eqs. (2) and (3) makes it a matter of great 
interest and importance to determine, by other experiments covering 
extended ranges of / -i- r, whether these forms with different constants 
may not apply to shapes other than that of the Phoenix columns. 

The results of the application of Eqs. (2) and (3) to Bouscaren's and 
the Phoenix experiments are not given, but the diagram shows that they 
would be satisfactory. 

It is a question whether the degree of distortion which accompanied 
the extremely high result of 65 867 pounds per square inch (shown at e in 
the diagram), was not considerably greater than that which would char- 
acterize the condition of ** failure " in actual structure. This important 
point cannot receive *too much attention in connection with short column 
tests, when the relative distortion, in the condition of "failure," is far 
greater than in long columns. 

When l-^r becomes larger than 60, the term log {1 -\ — 7~)» in Eq. 

(1) may be omitted. 



Digitized by VjOOQ IC . 



114 



No. 


r«. 


l-^r. 


Exp. 


P- 


P'- 


/. 


1 


8.94 


112 


36 160 


38 870 


34 488 




2 


J, 


« 


84 160 


•1 


•< 




8 


tt 


100 


86 270 


36 860 


86 040- 




4 


" 


t€ 


86 040 


it 


tt 




5 


it 


88 


36 670 


36 780 


36 692 




6 


n 


41 


84 860 


" 


" 




1 


*t 


It 


86 866 


88 100 


36 144 




8 


l( 


It 


36 900 


" 


" 




9 


" 


64 


36 680 


39 400 


36 696 




10 


it 


it 


86 680 


•( 


«« 




11 


ft 


62 


86 867 


40 600 


87 248 




12 


it 


(« 


37 200 


« 


" 




18 


(f 


40 


36 480 


41700 


87 800 




14 


" 


(( 


36 897 


" 


t* 




16 


<( 


28 


38 157 


42 800 


88 352 


40 360 


16 


(1 


" 


48 300 


u 


•• 


" 


17 


<•• 
« 

19. 37 


16 

2.7 
<« 

68.8 


49 500 
61240 
67 130 
67 800 
36 010 


44 300 
66 230 
88 900 




46 800 


18 




tt 


19 




67 140 


20 




tt 


21 


86 666 




22 


*' 


24 


42 180 


48 200 




42 160 









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115 

Discussion bt MANSFiEiiD Mbbbucaiy, J. M. A. S. C. E. 
Gordon's Formula has, on account of its theoretical basis, obtained 
a wide acceptance as an expression of the law governing the strength of 
columns longer than about twelve or fifteen diameters. If j4 be the 
cross-section of the column, P the load that breaks it, I its length, 
and d its least diameter, the crushing unit strength is according to this 
formula: 

A 12 

where the constants 8 and 7^ are to be determined rom experiments and 
depend upon the material, form of cross-section and arrangement of ends 
of the column. Two experiments furnish two equations from which the 
values of /S^ and 2^ may "be found. When more experiments than two are 
given, the values of S and T are to be deduced by the method of least 
squares. For experiments Nos. 1 to 14 of the paper of Messrs. Olarke, 
Beeves k Co., the most probable values of 8 and Tare thus found to be 

37 200 pounds and -99-^0^ > so that for these experiments the formula is 

P ^ 37 200 __ ... 

^' 1+ \^ I ^^ 

^22530 (/^ 

provided P be taken in pounds, A in square inches, and I and d both in 
the same linear unit. 

The form of Gordon's formula which uses r tiie least radius of gyra- 
tion in the place of d the least diameter, is preferred by many on account 
of its wider theoretical basis. For this case experiments Nos. 1 to 14 
give 

P^_ 37 200 

^ ~ 1+_J_ t 
^ 158 500 r= 

as the most probable formula. 

An inspection of the results of these experiments indicates that, for 

columns longer than about fifteen diameters, the decrease in the ultimate 

unit strength is approximately proportional to the length of the column 

expressed in diameters. That is to say 



,. (2) 



Digitized by VjOOQ IC 



116 

in whioh S and T are to be found from experiments for eaoh kind of 
column (and are not at all the same as the ^and Tin Gordon's formula). 
The application of the method of least squares gives 38 240 and 83.8 
pounds for the values of S and 7" from experiments Nos. 1 to 14, so that 

-4- = 38 240 — 83.8-^ 

A a 

is the most probable expression of this law. 

p 

The following table gives the values of the ultimate nnit strain —j- 

calculated from formulas (1), (2) and (3) for eleven different values of 

—or — , these eleven values being those corresponding to the fifteen 
tt r 



.(3) 



Nob. 


I 
-J 


I 

r 


Calc. (1) 


Gale (2) 
86 840 


Calo.(3) 


18 and 14 


16 


40 


86 840 


86 980 


11 and 13 


19.5 


52 


36 590 


86 590 


86 610 


ft* 


22.4 


62 


86 400 


36 880 


36 800 


9 and 10 


24 


66 


86 290 


86 290 


86 230 


31 


25.6 


68 


86 160 


86150 


36100 . 


7 and 8 


28.5 


76 


85 920 


85 920 


35 850 


fande 


88 


88 


85 490 


85 490 


35 480 


3 and 4 


87.5 


100 


35 020 


86 020 


85 100 


10* 


89.5 

■ 


108 


84 770 


84 640 


34 900 


^« and 29* 


40.7 


112 


84 660 


84 500 


34 830 


land2 


42 


112 


84 500 


34 500 


34 720 



long Phoenix colnmns, T4os. 1 to 14 and No. 21, experimented npon bj 
Messrs. Olarke, Beeves & Co., and the four Phoenix columns tested by Mr. 
Bouscaren in 1875, and reported in the Transactions of this Society for 
December, 1880 ; these four are marked with an *, For formulas (1) and 

j(d) the values of --t^t^^ used, and for formula (2) thosa of — . The 

p 
<H)rresponding values of -j for the three cases are given in the columns 

marked Oalc. (1), Calc. (2) and Oalc. (3). These exhibit a very dose 
agreement. 



Digitized by VjOOQIC 



117 



In the following table is given a comparison of the observed values 
of the nltimate nnit strength with those above calculated from the three 



formulas. 



The third column contains the values of -j- found by ex- 



No. 


I 
-d 


Observed. 


Dlflf. U). 


Diff. (2). 


Dlir. (3). 


13 


15 


36480 


-360 


— 360 


-500 


14 


15 


36 400 


— 440 


-440 


- 680 


11 


19.6 


36 860 


-j 270 


4- 270 


f 250 


13 


19.5 


37 200 


4- 610 


-f 610 


+ 590 


«• 


22.4 


37 500 


4- 1 100 


f 1 170 


+ 1200 





24 


36 580 


-f 290 


4- 290 


4- 850 


10 


24 


36 580 


-f 290 


-f 290 


4-350 


31 


25.5 


36 010 


— 150 


— 140 


— 90 


• 7 


28.5 


35 360 


— 560 


— 560 


-490 


8 


28.5 


36 900 


-}- 980 


i 980 


f 1050 


5 


33 


35 570 


-f 80 


4- 80 


4- 90 


6 


33 


34 360 


— 1130 


- 1130 


— 1120 


3 


37.5 


35 270 


-f 250 


4- 260 


4- 170 


4 


37.5 


35 040 


-f 20 


f 20 


— 60 


10* 


39.9 


31000 


— 8 770 


— 3 640 


— 3 900 


28* 


40.7 


34 800 


-f 140 


4- 300 


— 30 


«»* 


40.7 


86 600 


4 1 940 


4- 2110 


4- 1770 


1 


42 


35150 


+ 650 


4- 650 


4- 430 


2 


42 


34 150 


-350 


- 850 


— 570 



periment, and the fourth, fifth and sixth contain the differences between 
these observed values and those given in the first table. It will be seen 
that formula (2), which is theoretically the most satisfactory, exhibits no 
closer agreement than (1), and that (3), which is entirely of an empirical 
nature, gives nearly as close an agreement as any of the others— in fact, 
if experiment No. 10* be omitted, the precision of (3) is superior to (2). 
It hence appears that the simple formula 

-^ = 38 240 — 83.84 
A d 

may be said to represent very satisfactorily the ultimate strength of the 



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118 

Phoenix oolumns with flat ends and greater in length than abont twelve 
diameters, whioh have thus far been tested. 

DisoDSsioN BY C. L. Gates, J. M. A. S. C. E. 

From a graphical representation of strength of columns experiment- 
allj determined, as per foregoing paper, an intelligent analytical repro- 
duction of strength yalue for different lengths would at first seem out of 
the question. Yet, from the fact that experiments Nos. 13 and 14, 
showing unusual low limit of elasticity and, therefore, poorer quality of 
material, may be neglected and experiments recorded by G. Bouscaren, 
see Transactions, December 1880, for one, twenty-two, thirt^r-seyen, and 
forty diameters, change said average strength valae somewhat, lead me to 
propose for the consideration of the Society, for crippling strength of 
flat Phoenix column the following formula : 

^ _ 50 OOP — 2 oooyii 

^10 000 



in^y^icthfv^.u 



FJH, UN 
DOfitD 



i. $H0 



U^ULiflLM 



i^^ 



rt 



iLl 






nuuLcr 



prtoFoSEO 



ITU lit ;.»oi SC^P LH 



CURVE 



:.^^- 




6OO00tl# 



^50000 



4000O 



10 



aoooo 



which differs from Gordon's formula only in that the denominator instead 
of being a constant, represents the formula of a parabola whose apex is 
at 50 000 lbs. the assumed absolute crashing strength of wrought-iron, 
a not unreasonable supposition. 



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H9 

From above formula the strength Ttdues for different length columns 
would be as follows : 

B= 1 iSf = 48 000 

5 45 410 

• 10 43 250 

15 41 320 

20 39 420. 

25 37 650 

30 35 810 

40 32 200 

50 28 690 

60 25 380 

These values with the exception of the one at 15 diameters show only 

a discrepancy of from one to five per cent. 

The value derived from experiments of such magnitude, as in the 
foregoing paper published, can hardly be underrated and will be thank- 
fully received by the profession. 

Discussion bt Jambs E. Howard, C. E. 

The elastic limit of the Phoenix columns was established at that load 
where the apparent decrements of length ceased to be proportional to 
the increments of load which had caused them. 

In the absence of any definition, generally accepted, for the elastic 
limit, it has been customary with the Watertown Arsenal experiments to 
supply such data as would show the behavior of the material under test 
With some tensile specimens the elastic limit is so sharply defined that 
there would be no difference of opinion concerning it. In other cases its 
exact determination might be a matter of doubt. Subsequent tests of 
Phoenix columns, where the gauging-rods did not extend to the compres- 
sion platforms of the testing machine, but were attached to the column, 
showed smaller permanent sets than were found in this first series of ex- 
periments. Hence, it was probably correct to attribute a part of the per- 
manent sets found in these experiments to the condition of the ends of the 
columns and not to the metal itself. The manner of failure of latticed 
columns referred to one lot only, and as the results were not presented, 
as I supposed they were to be, remarks concerning them should not have 
appeared at this time. 



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120 

PisoussioN BY Thomas C. CiiABKe, M. A. S. 0. K 

It is very gratifying to the writer to know that the publication of the 
Watertown experiments on Phoenix oolamns meets with the approbation 
of so many eminent engineers who have taken part in this discussion. 

It is not too much to say that the paper and discussion together form 
a positive addition to our scientific knowledge. 

They have demonstrated that the mathematical theory of columns Ib 
correct ; and \}j slightly changing the constants of the usually received 
formula, as Mr. Bouscaren has done, or by a very simple new formula, 
as given by Mr. Whittemore, we can interpolate the strength of interme- 
diate lengths and sections of Phoenix colums, within the limits of these 
experiments. 

Some criticism has been made upon what Mr. Howard says in refer- 
ence to lattice columns. The report from Watertown contained some 
experiments on lattice columns which have no connection with these 
Phoenix column experiments, and they were omitted from the manu- 
script but by an oversight, the sentence objected to was not stricken out 
at the same time, as it should have been. 

It is hoped that others who have in their possession data obtained 
from experiments on the United States Testing Machine, will send them 
to this Society for publication, that they may have the great advantage 
of discussion by experts, as these experiments have had. 

It is hoped that a series of experiments will soon be made upon simi- 
lar Phoenix columns of steel, and that the results will be published and 
discussed by this Society. 

In the paper it was stated that the experiments were made at the cost 
of Olarke, Beeves & Go. 

The correct statement is, that these columns were ordered of the 
Phoenix Iron Company by the old United States Testing Board at a cost 
of 8775 00, and were paid for by that Board. That there being no money 
available to test them, the charge for this was paid by Clarke, Beeves 
& Co., and amounted to the sum of $43905. This statement is made, 
not only to correct what might be misunderstood, but to show how de- 
sirable it is that certain appliances should be added to the present United 
States Testing Machine, for the better handling of specimens, etc., so 
that the cost of testing may be reduced from 45 per cent of the cost of 
the material, down to not over 10 per cent, at least. 



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AMERICAN SOCIETY OF OIVIL ENGINEERS 

INSTITUTED 1802. 



TR AN 8 A.OTI01Sr8. 

NoTX. — This Society 1b not responsiblb as a body, for the facts and opinions adyanoed In 
any of its pnblibations. 



CCXXXIV. 

(Vol. XI.— April, 1882.) 



AVERAGING MACHINE. 



By W. S. Auchinoloss, Membbb of the Society. 



Bead Maboh 1, 1882. 



Daring the past year the averaging machine, illustrated by Plate 
XXni of Vol. X, has been remodeled and is now presented in a more 
compact and useful form, with wider range and greater capacity. In 
the original design, the representative weights on the platform were 
exactly balanced by equal weights in the scale pan, on the opposite side 
of the fulcrum. In the present device, the scale pan has been discarded 
and the representaitve weights are made to balance themselves over a 
common fulcrum acu By this means the weights handled are reduced 
one-half in amount, and the chances of error greatly diminished. 



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122 

In order to have the weights retained at certain relative distances and 
at the same time determine the location of their centre of gravity, it is 
necessary to hold them on a perfectly balanced platform, so that the 
weight of the platform will not enter the problem. There are many 
ways in which this factor can be eliminated and the desired result se- 
cured. For instance, the divisions between weights can be made part of 
an endless chain passing over and under the platform, or the platform 
itself might readily be balanced by a ball and lever ; but, probably, one 
of the simplest forms is that shown in the accompanying cuts. 




Fig. 1. 



The grooved platform rests on a saddle, (7, which in turn is sus- 
pended on the knife edges a, a. The saddle C carries four pulleys, d, 
d\ (V\ d"\ on its under side. These pulleys have grooved edges to re- 
ceive chains or wire ropes, g^ g\ g", g"\ The saddle (7 has also a rib 
on its under side, to secure the required amount of rigidity. The knife 
«dges are secured to the saddle by screws and slotted plates, so that the 
position of the centre of gravity of the platform and saddle can be 
varied at pleasure in a vertical direction, and a proper degree of stability 
secured. The edges of the platform are formed by two tubes, B, B\ 
slotted on their under sides. These tubes carry the counterweights F, 
F', The counterweights have the ends of the chains g, g\ g'\ g"\ 
fastened to their extremities B.if,f,f",f", and the other extremities 
of the chains are fastened to small screw-bolts at A, h'y h'\ h"\ The 
screw-bolts pass through the ends of the platform and the chains are 
drawn taut by milled nuts, and kept so by lock nuts. The knife edges, 
or trunnions of the saddle, rest on the standards h, b. 



Digitized by VjOOQIC 



123 

When the machine is first pnt together, the saddle is hung by its 
trunnions on the standards and its weight is increased on the lightest 
side, until the balance is secured. The counterweights are then made of 
such weight, that they exactly equal the combined weight of platform, 
paper scale, screw-bolts, nuts, and bolt wires, plus the weight of excess 
of chain (pendant from the platform over that pendant from the extrem- 
ities of the counterweights). The latter factor will always be a constant 
quantity. Having secured the above equality, the counterweights are 
placed in the tubes, the platform in the saddle, and the chains adjusted 




Fig. 2. 

around the pulleys. It will be observed, that when the platform rests 
centrally on the saddle, the two counterweights will also be located with 
equal lengths overhanging the opposite sides of the saddle. If, then, the 
screw-bolts are properly adjusted, the entire system will be in equipoise. 
The next adjustment is to draw out the platform A its full dist&noe in the 
direction of the arrow No. 1. The counterweights will immediately be 
projected an equal distance in the opposite direction, and as their weight 
exactly equals the combined weight of the platform and its parts, the 
equipoise should be as perfect as that found for the mid position of the 
platform. When both of these adjustments have been carefully made, 
it will be found that no matter where the platform may be subsequently 
placed, it will continue in perfect equipoise. 

With this result accomplished, we can place on this equilibrated 
platform any combination of representative weights, and by drawing out 
the platform to its balancing point, the location of the centre of gravity 



Digitized by VjOOQIC 



124 

of the system will at once be indicated on the scale bj the pointers over 
the trunnions. 

The representative weights may for convenience be arranged on the 
decimal system, thns E, D and Ay may represent units, tens, hundreds ; 
while C and B represent 5 and 50. 

The same weights may be used to express multiples, or factors of 
these quantities, and consequently serve for the solution of a great 
variety of problems. Each machine is supplied with several paper 
scales, suitably divided for different purposes. 

When the problem is one of time, the scale represents months and 
days. When one of proportion, the scale has its zero point at the centre 
of its length, and the subdivisions branch in both directions. When the 
question is that of location of the centre of gravity of a system from a 
fixed point; the zero is located at one extremity of the scale ; and so on 
for different objects to be attained. A convenient size of platform is 
one 29 inches in length by 9 inches in width, having 63 transverse 
grooves. Such a machine can be made to weigh less than 13 pounds. 
The range of the platform is not limited by the 63 grooves, for if a 
weight should happen to fall midway between grooves (t. c, upon the 
ridge), one-half of the amount can be dropped in one groove and the 
remaining half in the other, without altering the result. So also it is 
possible to lodge 3 parts in one groove and 1 part in the other, and se- 
cure exactly the same effect as if we had 4 grooves at our command. It 
is clear, therefore, that 63 grooves can be made Jo answer the purposes 
of 126, or of 252 grooves, as the case may require. The final reading of 
the index pointer can be made with great exactness by means of a finely 
divided scale, and the exact balance can be indicated by aid of a small 
spirit level attached to the platform. 

With this wide latitude the averaging machine may be used for find- 
ing the average date of purchases extending over a period of 8 months. 
By reversing the paper scale, about the average date as a centre, the 
credit side of the ledger can be laid off, the paper scale returned to its 
original position and a new date found, which will express the average 
of both the debit and credit sides of the account. For purchases cover- 
ing only one month, the average can be determined to an hour. 100 
accounts of this character can readily be solved in one hour's 
time. 

The averaging machine offers the cotton broker the most rapid 



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125 

means for determining the average price of ** futures,'* whether the same . 
are figured in pence English, or in cents of our own currency. 

Thus far we have dwelt only on the commercial aspect of the subject. 
It also has its direct bearing on the question of average haul 

Omitting the rebate due to *' limit of free haul " (which is purely a 
matter of contract), we have by the principle of moments : 




Fig. 3. 



With stations 100 feet apart : 



Average haul = 



{B + 2C+32))xl00 + Jq, {F +20 + 3 H)x 100 + Ee. 
A + B-\-C+l) "^' E-Jf-F+G + H 

Whenever the limit of free haul = 100 feet, then A,ay E^ e are in 
effect = o, and : 



'B + 2(7+32) .F±2G + 3 



f + BHn 



xioo 



Average haul =[- ^^^^^ -^ F+QT 

The above formuke are based on the assumption that each mass B, C, 
D, Sec, has its centre of gravity directly over the respective stations 
8, 2, 1, &c. 

Whenever a greater degree of accuracy is required the sections can 
be made of half size, which will give stations 50 feet apart, instead of 100, 
and the computations can be made accordingly. 

By aid of the averaging machine the respective distances between the 
centres of gravity of the excavation and of the embankment (from the 
station No. 4) can be severally determined, and their sum will equal the 
total average haul ; from which the limit of free haul must de deducted. 

By this method it is evident that representatives of the amounts in 
the respective sections of the embankment, need only be placed in proper 
order on the platform of the averaging machine — a single pull given to 
secure the equipoise— and the haul of excavation can be instantly read 



Digitized by VjOOQIC 



126 

off from the paper scale. If the same processes are repeated for the 
embankment, the total ayerage haul will be determined. 

The averaging machine can also be used advantageously in the solu- 
tion of many problems that occur in ship building, location of marine 
engines, boilers, etc., etc. 

A moment*s thought will show clearly that the chances of error are 
greatly reduced, and valuable time redeemed by the use of this machine. 

In the wide range of problems relating to averages, probably few will 
present themselves, which cannot find a ready solution upon an equili- 
brated platform of greater or less magnitude than the one herewith 
described. 



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AMERICAN SOCIETY OF OIVIL ENGINEERS. 

INSTITUTED 1852. 



TIli?L]Sr8A.CTIO]Sr8. 

Note.— This Society is not responsible, as a body, for the facts and opinions advanced 
in any of its publications. 



ccxxxv. 

(Vol. XI.— April. 1882.) 



ON THE REMOVAL OF INCRUSTATION IN WATER 

MAINS. 

A Description of the Operations Performed in Halifax, 

N. S., Canada. 



By E. H. EEATiNa, M. Inst. C. E., Cmr Engineeb and Enqineer 
OP THE Water Works. 



Read March 15th, 1882. 



The City of Halifax is sapplied with water from two distinct sources. 

The high service supply is drawn from the Spruce Hill Lakes, elevated 
360 feet above city datum or mean low-tide, and about 8 miles from the 
heart of the city. The main consists of 6 500 lineal feet of 20 inch, and 
29 500 feet of 15 inch pipe, and furnishes water to all localities, exceeding 
about 125 feet above tide level. 

The low service supply which delivers water to nearly all the remain- 
ing portion of the city is drawn from Lower Chain Lake at an elevation 



Digitized by VjOOQIC 



128 

of 199.40 feet above the same datum, and aboat 4 miles from the heart of 
the City. 

The main is a continuous one of 24 inches in diameter, and about 
13 500 feet in length. It was laid in 1862, was cast in Glasgow, and was 
well coated with a preparation of coal tar pitch apparently the same as 
that known as the patent of Dr. Angpis Smith. 

All the pipes of the high serrice main were also made in Glasgow. 
The 20-inch and the first 16 100 feet of the 15-inch pipes were laid in 
1868, and were similarly coated to those above described. The remain- 
ing 13 400 feet of 15-inch pipes were laid in 1856, and do not now appear 
to have been originally coated with any preservative preparation. 

The Engineers who advised the construction of the works, estimated 
the capacity of the high service main at 2,000,000 gallons and the low 
service main at 5,000,000 gallons daily. 

There was not and is not yet any ready method by which the actual 
quantity of water delivered into the city could be measured or gauged 
with any degree of accuracy. It became evident, however, after the lapse 
of years, that the works were not performing anything like their esti- 
mated duty, and that their capacity was gradually decreasing. The 
pressure ultimately became so poor in some localities that the water 
would not flow from the nozzles of the hydrants, nor even in the base- 
ments of some of the houses. 

The efforts made to overcome the difficulty consisted in : 

1. Energetic searches after underground leaks. 

2. The partial or entire closing of many of the valves on the distribu- 
tion mains throughout the city. 

3. The partial diversion of the high service supply into the low ser- 
vice system of pipes. 

4. The substitution of larger pipes in some localities. 

5. A general inspection of all the internal pipes and fittings, with in- 
structions to shut off the supply wherever excessive waste was detected. 

6. The passing of an ordinance authorizing fines to be imposed for 
the " unnecessary waste " of water. 

These provisions did not greatly lessen the eviL Complaints of 
** short supply'* and of <' no supply at all** continued to be made, and were 
annually on the increase. Instances are on record when some hundreds 
of such complaints were made in a single day. The difficulty, of course, 
was most generally felt during the winter season, and especially duriug a 



Digitized by VjOOQIC 



129 

sharp snap of frost, when many householders—to avoid the risk and 
dangers of frozen service pipes — are in the habit of allowing a copious 
stream to run from every faucet on their premises. 

The author first became connected with the works in 1873. After 
carefully going into the original calculations he became satisfied that the 
Engineers who first reported upon the discharging powers of the mains, 
had not made any mistakes in that respect, t*. e., assuming the generally 
accepted rules to be correct. They had, in fact, judiciously, rather un- 
derstated their capacity. A very short time, however, elapsed before 
the principal cause of the troubles was found to be within the pipes 
themselves, in the shape of a rough, hard and thick incrustation of oxide 
of iron. Although it had long been known that the pipes were badly 
corroded, the actual extent to which this corrosion existed, and its dam- 
aging effect upon the water supply, did not appear to have been suspected. 

In some of the oldest pipes the concretion was found to be over li-inch 
in thickness. Many miles of pipes of 3 inches in diameter had originally 
been laid within the city ; these were in some places almost closed 
against the passage of water, and the old 6 inch pipes were reduced in 
internal diameter to from 3i to 3} inches. The mains leading to the city 
were, on examination, found similarly incrusted, though to a smaller ex- 
tent, as they had not been as long laid as the pipes above described. 

The first attempts to remove the incrustation by mechanical means 
were made in 1875, w^en over 5 miles of the old 3 inch distribution pipes 
were cleaned by a scraper attached to iron rods and propelled by hand. 
The machine consisted of four arms or knives attached to a centre and 
sprung outwards against the inner surface of the pipe by a thick rubber 
disk. The usual process was, after cutting out a length of pipe, to insert 
the scraper, turn on a good ruu of water against it, and gradually work 
it ahead for 150 or 200 feet. A small steam pump was used to keep the 
trench clear of water. The pipes cleaned in this manner had been laid 
for about 28 years. The following quotations on this subject are from the 
dvio report of 1875. ' ' It has been customary during the last six or seven 
years, as these pipes were found gradually to fill up by oxidation and 
concretions, and became insufficient for the supply, to lift them and put 
down pipes either of the same or larger diameter. On examination dur- 
ing the past summer, it was ascertained that those still remaining-— of 
which there are about seven miles — had contracted to li and 1^ inch in 
size. * * *." 



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180 

" The work of boring or scraping ont five miles of these old pipes, and 
restoring them to their original internal diameter, was given to contract 
for $3 750, or at the rate of $750 per mile, the city supplying the neces- 
sary new pipes and sleeves to make good the connections. The con- 
tractor was held responsible for any damage that might resolt in the 
process of cleaning, and he was not allowed to have the water tamed off 
of any street or district for more than twenty-four hours." 

In the following year 6 385 lineal feet of 3-inch water-pipes were 
cleaned out in a similar manner by the same contractor and at the same 
rate as previously paid, viz. : 14 i^o cents per lineal foot. There were 
extras on account of old leaks discovered and repaired, to the amount of 
129.86, making the total cost ^936.53. 

The author considered the rates paid on the above contracts ex- 
cessive, but his advice that the work should be done by the Water 
Department by days labor was overruled. The process, although effective 
for a time — ^besides being slow, laborious and expensive —was practically 
inapplicable to pipes of large diameter, and it; was the incrustation in the 
large pipes which was so seriously affecting the water supply to the city. 

The first effort to remove the incrustation from the larger pipes by 
mechanical scrapets was made in 1880, the following description of which 
is quoted from a local newspaper of the 14th October of that year : 

"It may not ba generally known outside of engineering circles that 
cast-iron water-pipes, after being in use a few years, become more or less 
corroded, so as to seriously affect the flow of water through them and 
diminish the water pressure which, when new, they are capable of 
affording. 

''This matter has for some time been under consideration by our 
Board of Works, who latterly, on the advice of the City Engineer, 
decided to try the experiment of scraping out some of th<) large pipes 
by means of a novel little machine known as a mechanical pipe scrapcg^ 
******** and yesterday, at three o'clock, 
was fixed upon as the time for the trial. The pipe selected for the experi- 
ment was one of twelve inches in internal diameter, leading from St. An- 
drews Cross over the North Common and down Cogswell street as far as 
Brunswick street, a length of 3 200 feet " (Plate in. ) * * This pipe was se- 
lected by the Engineer on account of its being the oldest in the city, hav- 
ing been laid by the late Halifax Water Company in 1848. The thickness 
of incrustation on the inside of the pipe had been observcvl to be a little 



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131 

more than one inch, so that the indde diameter was aotnally reduced to 
less than 10 inches, besides being very hard and rongh. The North Com- 
mon being at a high level, with inclinations both down and np-hill, and 
the pipe being the worst one known, it was considered that, if the experi- 
ment on this length proved snocessfnl, there could be no risk in under- 
taking to scrape out all the pipes through the streets and themains from 
the lakes. A few gentlemen, including the press reporters, who had 
taken an interest in what was going on, assembled at St. Andrew*s Cross 
to see the machine put into the pipe and started on its journey. The 
pipe cover having been securely bolted to its place, the water was turned 
on at 3.30 o'clock p. m., and although the watchman in the trench, and 
others stationed along the line with their ears to the ground, reported 
that they could not detect any movement in the machine by the sounds 
it was expected to make while passing along, the watchman, with his ear 
to the pipe about a quarter of a mile off, soon came running to say that 
the scraper had passed his station about five minutes after the water had 
been turned on. A general rush was then made for the outlet at the foot 
of Cogswell street, where it was expected to emerge almost immediately. 
On arriving at that point, a large stream of black water was seen rapidly 
issuing from the open end of the pipe, but this soon ceased, and it was 
feared that the little machine had stuck fast in the pipe at some point, 
and was lost somewhere within the last half mile. Just as all hope for 
its reappearance was about to be given up and the experiment pronounced 
a failure, a dense mass of ' black muck ' of many tons weight was sud- 
denly seen to issue from the end of the pipe, and immediately afterwards 
a perfect torrent of black and muddy water. This occurred about thirty 
minutes after the scraper had been started, and it was then known that 
the machine had performed its task and must be somewhere embedded 
in the heap of iron rust, mud and dirt in the trench. The water having been 
shut off and somewhat subsided, the scraper was then fished up out of the 
trench, greatly to the relief of mind of all concerned. Arrangements were 
then made for passing it through the same length of pipe a second 
time, so that it would be more thoroughly cleaned ; but the party as- 
sembled being perfectly satisfied with the first trial, dispersed.'* 

The next operations of the same kind were performed on the Bruns- 
wick street 12-inch main for a length of 3 800 feet ; but owing to obstruc- 
tions in the pipe, the piston leathers being much worn and the steadily 
rising gradient which had to be overcome, the scraper was four hours in 



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132 

making the first trip. It halted in its progress on several occasions, and 
once remained stationary for so long a time that it was feared the main 
would have to be cut open to get it ont. The second run was made in an 
hour and fifteen minutes, with the piston leathers in the same worn out 
condition, and the next in a somewhat shorter time. 

This concluded the operations for 1880. The scraper so far used 
being the experimental one, imported from an engineering firm in Kil- 
marnock, Scotland, the cost of which, landed in Halifax, was $114.11. 
Further particulars as to the cost of the work, etc., will be found in the 
Schedule, under headings Numbers 5 and 7. 

The results obtained from these experiments were only partially 
satisfactory. They showed that scraping machines could be cheaply 
driven by water pressure alone through the large pipes ; but as it was 
found on examination— after the passage of the scraper several times 
through the pipes—that all the incrustation had not been removed, some 
improvement would have to be effected before the method could be pro- 
nounced perfectly successful 

In 1881 the author had made, under his own directions, new scraping 
machines for the 24-inch, 20-inch, 15inch, 9-inch and 6-inch pipes, and 
proceeded to operate on the mains shown in Plate m. (which is a 
general plan of the Works), and more particularly described in the 
Schedule. 

The design adopted for the scrapers was substantially the same as 
that of the experimental machine, with the exception that, in the large 
scrapers, small additional springs were attached to the pistons, in order 
-—on account of their great weight — to keep them as nearly as possible in 
the centre of the pipe, and in all of them strong rubber springs were 
inserted beneath and a little in front of the knives or cutters, so as to 
ensure, as far as practicable, their contact with the interior of the pipes. 
(See Fig. I.) These rubbers were not attached until after a scraper had 
made one run without them, as it was feared that the extra friction 
caused by them would occasion stoppages, if used in any pipe that was 
badly corroded. 

The 24*inch low service main was the next selected, and the first por- 
tion operated upon was the end nearest to the city. The scraper was 
inserted in the hatch-box at St. Andrew's Cross, with the intention of 
sending it westwardly, or in a direction opposite to the natural flow of 
the water in the main, on account of the steep rise in the gradient from 



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133 

the bead of the Northwest Arm towards the oitj. (See Plates in and IV. ) 
It was subsequently found that this precaution was unnecessary, as the 
machme, although it weighed about 1 000 pounds, could be propelled 
up-hill with as much certainty as on a level or in a downward direction. 
The scraper was started by turning the high-service water into the low- 
service main behind it. It traveled off at a low and pretty regular rate 
of speed, making a rumbling noise as it went— so that it could easily be 
followed and its exact position readily detected, except when the sounds 
•were drowned by the rattle of passing vehicles— «nd passed out with great 
force at the open hatch-box near the head of the Arm in just one hour 
after it had been started. The pressure indicated on the gauge attached 
to the 24-inch main at St. Andrew's Cross never exceeded 6 pounds dur- 
ing the operation, and the distance between the hatch-boxes or the length 
traveled was 6 875 feet. After the machine was given another run through 
the same length, it was removed to Lower Chain Lake and inserted 
in the 24-inch main at the hatch-box at that point. The head of water 
on it was from 9 to 10 feet, but as it was considered doubtful that this 
would be sufficient, a connection with the high- service supply was previ- 
ously made by means of a 15-inch pipe, so that the pressure could be 
increased if wanted ; this, however, was found unnecessary, as the scraper 
started off— without any assistance from the high-service — at a good 
brisk pace, and its speed increased so rapidly as it advanced down- 
hill (see Plate III), that the workmen were unable to keep up with 
ii The distance from the starting point to the hatch-box near the head 
of the Arm, where it emerged, was 6 525 feet, and the time taken to 
travel this distance was, in its first run, 15 minutes, and in the second 12 
minutes. The latter or intermediate hatch- box was then closed, and the 
scraper was sent through the whole length of the low-service main, a dis- 
tance of 2 miles 200 feet, in one run, which it accomplished in two hours 
in the first and 1 hour and 50 minutes in the second trial. Its rate of 
speed varied greatly, taking in the first instance 15 minutes to travel the 
first 5 000 feet, 14 minutes to the next 1 525 feet or to the intermediate 
hatch-box, 16 minutes to reach the Quinpool road, a distance of 1 700, 
and 75 minutes to St. Andrew's Cross, 5 175 feet. In the second instance, 
the same points were passed in 14, 13, 15 and 68 minutes respectively. 

By looking at the profile (Plate III) it will be seen that the 20-inch 
high service main is at high elevation, and is not far from a level gradient 
for its whole length of 6 500 feet. As it was feared that the normal pres- 



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134 

Tire of the water would not be sufficient to force the machine through this 
pipe the proper attachments were made, and a pumping engine was sent 
to Spruce Hill Lake in order to increase the pressure if it should be 
found necessary. The scraper was inserted at the hatch-box near 
the lake, shown in Plate HI, and although there were only 8 feet 10 
inches of water above it, it started off and completed its journey of 6 000 
feet to the next hatch-box at the commencement of the 15-inch main in 
37 minutes without any assistance from the steam pump. The second 
run through the same main was made in M minutes. 

The 15-inch high service main was then cleaned out in three sections, 
as indicated by the positions of the hatch-boxes shown in Plate m, 
their respective lengths being 16100, 6525 and 6875 feet. The 
«craper in its first run travelled the whole length of the finbt section 
in 1 hour and 1 minute, the second in 1 hour and 10 minutes, and in the 
third section, which was that nearest to the city, it stuck fast at about 600 
feet from the hatch-box near the head of the Arm. It was at the time 
working under a pressure varying from 45 to 50 pounds on the square 
inch, and after it stopped in its course the gauge indicated 65 pounds. 
The valves were then opened full and the pressure gradually increased 
up to 101 pounds, which was the limit attainable at that point. All this 
proved of no effect as the scraper still remained stationary, and the main 
had to be cut open to get it out. Its presence was easily detected by the 
noise made by the water rushing past it when a high pressure was main- 
tained. On opening the main it was found firmly wedged into the pipe 
by a large piece of lead of irregular shape, weighing about 30 pounds. 
In laying the pipes this lead had run through one of the joints, and 
hence caused the stoppage. Other large pieces of lead, besides stones 
of all sizes (the largest about 9 inches in diameter), a sledge hammer and 
pieces of broken pipes were brought out by the scrapers at other times ; 
but this was the only occasion where an obstruction of any kind caused 
a stoppage in the machine so that it had to be cut out. 

The pipe was then made good and the scraper again started off on the 
third section, through which it passed, without any further trouble, in 
35 minutes. After some further operations on these sections separately the 
scraper was sent through the whole length of the 15- inch main in one run. 
It was inserted at the end of the 20-inch main and the full pressure gradu- 
ally turned on. The hatch-box at Lower Chain Lake (16 100 feet) was 
passed in 1 hour ard 5 minutes, the hatch-box near the head of the Arm 



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135 

(22 625 feet) in 1 hour and 40 minutes, and St. Andrew's Cross (29 500 
feet) was reached in just 2 hours from the time of starting, making the 
average rate of speed nearly 3 miles per hour. 

The pipes cleaned in the previous year were then recleaned with the 
improved scrapers, new hatch-boxes were provided where they had 
previously been omitted, and permanent brick man-holes were built, a 
full account of ftie expense of which will be found in the following 
schedule : 




Fig. 1 




STEEL SPRING 



^BHWW^nnmm^^ j l^ 



Fig. 2. 



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136 





y been 
prepara- 
found 
nodules, 
eter, ir- 
pe thor- 










§J3 ^m3 






!- .t3 .t2 "^ . 






This pipe had appi 
coated with Dr. Sm 
tion. The surface 
nearly covered w 
from ^ to 1 inch in 
regularly distributed 
oughly cleaned. 




Foot. 


. 00 

a cc 




fi 


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yt 


5S 


o 




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138 



Remarks. 


The improved scraper used in re- 
cleaning brought out a very large 
quantity of incrustation ; appar- 
ently as much as taken out by 
original scraper in 1880. Pipe 
left perfectly clean, as far as 
could be ascertained. 


This pipe was probably not coated 
originally with any preparation. 
Average thickness of incrustation, 
about f*. No man-holes bu'ilt. 
Pipe only imperfectly cleaned. 

1 

5 894 


Coetper 
Lineal Foot. 


Cents. 

1.084 
3.483 


Total. 


«» 




s 

1 


Cost of 
Labor and 
Materials. 

34 69 
'76 76 


1 




Cost of 
Materials. 

19 60 






^S 










Reoleanimo No. 5 in 1881. 

Cost, exclusive of scraper, but in- 
cluding one new hatch box 

Man-holefi. brinir in cement 




12" Pipe.— Brunswick street. 

Length = 3 800 feet. 

Ori^nally laid elsewhere in 1848. 
Taken up, cleaned by hand, and 
laid in present position in 1862 
and 8. 

Cleaning (including one-half cost 
of scraper and one hatch-box 
only) 


& 


« 






fc* '0881 u| 9aop 3[J0ii 



Digitized by VjOOQIC 



139 



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Digitized by VjOOQIC 



140 

No. 10, which was a pipe of 6 inches in diameter, was the smallest* in 
which the attempt was made to remove the incrustation by means of a 
self-acting scraper. The thickness of the incrustation in this case aver- 
aged fully li -inches, and the difficulty experienced in removing it, even 
for the short length of pipe operated upon, was considerable. The 
scraper would only travel a few feet at a time, and would then become 
firmly embedded in the iron rust which accumulated in a dense mass 
ahead of it, preventing its further progress. After several attempts to 
force it through, which were attended with some breakages and involved 
cutting the pipe to get it out, the operation was abandoned for the season, 
as wet weather began to set in, and it was evident that some other kind 
of machine or method of procedure would have to be adopted in order to 
remove the great bulk of the corrosion before the ordinary scraper would 
pass through as it had done in the other cases. A new and smaller machine, 
capable of being extended to the full diameter of the pipe, is now being 
made with only four arms and knives instead of eight. The centre rod 
is in one piece and hollow, with a nozzle at the front end, the object of 
which is to have a powerful jet of water playing immediately in front of 
the scraper to remove and prevent the detached iron rust from forming 
into a solid mass so great as to cause an obstruction. If this plan should 
not prove successful it is probable that, in order to clean all the small 
pipes, which are badly corroded, they will have to be opened temporarily 
in short lengths of 400 or 500 feet and the scraper be pulled through for 
the first time with a wire rope, after which it is not anticipated that there 
will be any difficulty in propelling it by water pressure alone. 

The entire expense attending these cleaning operations, where the 
pressure of water only was used as the motive power, including the cost 
of hatch-boxes, man-holes and the drains from them to the nearest sewers, 
repairs to the machines and to broken or damaged pipes, and all other 
charges connected with the work, was, as the schedule shows, $2 777 47. 
If, however, we deduct No. 10, which is only partially done, and Nos. 6 
and 8, which are for recleaning the pipes scraped out in 1880, the cost ' 
will stand as follows : 

Total length of old 24-inch, 20-inch, 15-inch and 12-inch pipes 
cleaned = 62 800 lineal feet, or nearly 12 miles. 

Total cost, not including man-holes = $1 768 50 = 2.816 cents per 
foot. 

Total cost, including man-holes = $2 215 38 = 3.528 cents per foot. 



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Digitized by VjOOQ IC 



Digitized by VjOOQIC 



141 




-'-'fir »r f^m^ 



III 



Digitized by VjOOQ IC 



142 

It should, perhaps, have been mentioned that no pumping apparatus 
was needed to free the man-holes of water, as in most oases thej were 
connected with the sewers bj short drains and where no sewers existed 
within a convenient distance thej were allowed to overflow. 

Fig. 1, page 135, is a drawing of one of the large scrapers as nsed in the 
final operations. The cutters or knives were found to wear down rap- 
idly after a machine had been a short time in use, so that they soon be- 
came almost useless, and others had to be added. To obviate this diffi- 
culty in the future the author is now having made chilled cast iron cut- 
ters, as shown in Fig. 2, which can be simply bolted to the end of the 
steel spring and replaced at a few moments* notice without the necessity 
of sending the scraper to the machine shop. 

The effect of removing the incrustation from the mains was .most 
marked and beneficial upon the water supply to the city, and will be at 
once seen by comparing the pressures taken at the 25 hydrants on the 
wharf properties along the harbor in the month of February, 1880, 1881 
and 1882. 

In making a comparison it is, however, necessary to bear three things 
in mind which tend to show that the result of these partial cleaning 
operations has been even more favorable than the pressures would indi- 
cate. They are as follows : 

1st That the incrustation in the pipes was annually rapidly increas- 
ing and the pressure was consequently decreasing. 

2d. That in 1880 and 1881 the high service supply was augmenting 
the low service, which supplied the hydrants on the wharves, and that in 
1882 this was no longer the case. 

3d. That in the winter of 1881 a pretty rigid inspection to detect and 
prevent waste was maintained, and fines were imposed wherever it was 
brought to notice. There was no inspection made in the winter of 1880» 
nor has there been any during the present winter of 1882. 

The total pressure on the 25 hydrants in February, 1880 = 856 pounds^ 

or an average of 34.2 pounds each. 
The total pressure on the 25 hydrants in February, 1881 = 1 088 pounds, 

or an average of 43.5 pounds each. 
The total pressure on the 25 hydrants in February, 1882 = 1 309 pounds, 

or an average of 52.4 pounds each. 



Digitized by VjOOQIC 



143 

If we omit from the comparison the preBsnres taken in February, 
1881, as thej certainly should be omitted, on account of the efforts made 
in that year to suppress waste, the result shows that the effeotiye pressure 
in the city has been increased a little over 50 per cent., without taking 
into account the fact that the High Service Supply no longer aids the 
Low Service, as it did in 1880 and 1881, but that it is now confined to 
within its own limits. 

If we now turn to the High- service, probably the best example to 
take will be the highest part of the city supplied with water, which is 
in the neighborhood of the new cotton factory. The most elevated plug 
in this vicinity is at the intersection of Almon street and Kempt Boad, 
and the pressures taken at the same times as those previously given 
stand as follows : 

The pressure taken in Feb., 1879, was 8 lbs. on the square inch. 

« U « (« IgQQ^ C( Q it a it 

(i <( (c (( 1881 *' 28 " ** ** 

ic ti <( i( 1032, " 34 " ** ** 

Although this example shows an increase of over 400 per cent since 
1880, the actual increase in the whole service, though very greatly aug- 
mented, is not truly represented, as it was nothing like that amount ; 
still it shows truly the effect at that point. 

Other examples quite as striking could be given, and at several 
points where formerly the water would not flow from the nozzles of the 
hydrants, there is now a pressure of from 12 to 19 lbs. on the inch in the 
coldest weather in winter, and up to the present date (23d February, 
1882) there has not been a single complaint of insufficient supply since 
the winter began, where formerly there used to be hundreds. 

During the past summer the author was consulted with reference to 
removing the incrustation from a 6-inch main (which was very badly 
corroded) supplying Mount Hope Lunatic Asylum, in the town of Dart- 
mouth. The pressure some years ago had become so poor that the 
water would not rise to the tanks in the top of the building without the 
aid of a steam pump, which had to be kept going almost constantly ; but 
ultimately even this provision was found insufficient, as the main did 
not deliver the water quickly enough to keep the pump going at a mod- 
erate rate of speed. 



Digitized by VjOOQIC 



144 

The commissioDers for the asylum, who contemplated laying a new 
and larger main, were advised to try the effect of cleaning operations, 
upon which advice they acted. 

The main, which was 1^ mile in length, was found reduced by the 
corrosion to about 4 inches in internal diameter, and as the head of water 
at the upper end was small, a steam fire-engine was employed to force 
the scraper through. In the first trial the machine only traveled about 
70 feet, when it stopped at an old break in the pipe and had to be cut 
out. After repeated trials, in which, at times, the pressure was as high 
as 120 lbs. on the inch, it was found that the stoppages caused by 
obstructions of various kinds were so many that the commissioners be^ 
came disheartened, and, without attempting any alteration or improve- 
ment in the scraper, they decided to change the method of procedure— r 
to open the main in short lengths and to pull the machine through by 
manual labor. At this time the scraper had gone only about 1 000 feet. 
A great many obstructions were encountered under the altered j^lan in 
the shape of lead and stones, and in one case a large piece of wood 
caused a stoppage. Sometimes the machine could be drawn ahead only 
a few feet, when the main would have to be again cut to extricat<^ it. 
Finally, after the obstructions and the great bulk of the rust had been 
removed, the scraper was sent through the main from end to end, with- 
out any assistance from steam power, and it traveled the whole distance 
in 27 minutes. Permanent hatch-boxes and man-holes were then built 
at each end, so that the machine can now be sent through as often as 
desired, at very trifling expense. 

The following is a statement of the cost of these operations : 

Labor list $291 70 

Materials 116 83 

Hire of engine 160 25 

Halifax Board of Works for pipes, sleeves, 
hatch-boi(es, scraper and labor . .*. 362 36 

Total $931 U 



or 14.108 cents per lineal foot. 

The effect of cleaning this main was immediately felt at the asylum. 
There is no further occasion for the stationary engine and pump to 
force the water to the tanks, as they now overflow by the force of gravity 



Digitized by VjOOQIC 



145 

alone, and it is stated that the saving in the one item of coals will be 
about $700 per annum. 



In discussing the above paper several qnestions were asked, which the 
Secretary transmitted to the anthor, Mr. Keating, and received the fol- 
lowing answer: 

In reply to yonr communication asking for some farther information 
respecting the pipe cleaning operations carried out in this city, together 
with an analysis of the water, as a supplement to my paper on '* The 
Bemoval of Incrustation in Water Mains," I have much pleasure in 
submitting to yon the following remarks, in which I will endeavor to 
answer the questions which have been raised. 

All the large scraping machines used in our operations were made on 
the same principle, as shown on the drawing submitted (Fig. 1). They 
are extremely simple, consisting of a stout centre wrought iron rod, in 
two pieces, coupled together in such a manner as to allow of a little 
play, so that the machine may pass round any ordinary bends or angles 
in the pipe line. There are eight arms of spring steel, varying in width 
and thickness, according to the diameter of the pipe. Each of these 
arms has barbed cutters attached to it, which do all the work in remov- 
ing the incrustation from the pipes, the backward set of four being so 
placed as to cut away everything that may have escaped the front set of 
cutters. The arms are also so arranged that they will yield inwards in 
case of the cutters striking against any solid obstruction, such as a ferrule 
projecting into the pipe, which would otherwise cause the machine to 
stop. The forward part of the cutters is tapered towards the centre of 
the pipe, with the double object of cutting or splitting longitudinally any 
heavy incrustation of iron rust, and also of preventing the barbed knife 
from catching in any defective or open joint in the pipes, which would 
also cause a stoppage. The pistons do all the work in propelling the 
machine forwards ; they are made double in order to ensure steadiness, 
and they do not do any cutting work whatever. Each is composed of a 
he&vy disk of cast iron, at the back of which the leathers are placed, 
attached to small leaden or cast iron plates, in sections, so as to give 
them additional stiffness in one way, and yet so as to allow them to yield 
backwards, to pass any obstruction not removed by the cutters. The 
small springs attached to the pistons are placed there for the purpose of 



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146 

maintaming the machine exactly in the centre of the pipe, which pro- 
yision is necessary in all large scrapers, on account of their great weight; 
these springs also preserve the leathers from being rapidly worn out. 
The heavy rubber springs must be regarded as auxiliary to the main 
springs or arms, and should not be attached until the machine has made 
one or two runs through the pipe without them. If other and heavier 
steel springs are provided for final operations, the rubbers may be dis- 
carded. The large rings at each end of the scraper are of no service ex- 
cept for convenience of handling, and in the case of small scrapers for 
the purpose of hauling them through the pipes in the event of that 
becoming necessary. In the manufacture of any new machines, I would 
substitute a heavy nut in the place of each of these rings. The new 
knives or cutters which— it was stated in the original paper — were to be 
made of cast iron chilled, are now to be made of oast steel. 

The scrapers are all propelled forwards in the direction of the barbed 
cutters, the pistons being hindermost. They cannot be forced through 
the pipe in the wrong direction, i. 0., with the pistons foremost, as the 
leathers would bend over, and the greater portion of the force of the 
water would be lost ; and if the machine should move a short distance, 
it would soon be brought to a standstill by the comers of the knives 
catching in the slightest irregularity in the pipes, or in any joint that 
might happen to be a little open. 

With regard to the coating on the pipes, I can only say, that where it 
has been used at all (see remarks in the schedule), to all outward appear- 
ances, it is the same as that known as the preparation of Dr. Angus 
Smith. In the case of the 20-inch high service main laid 13 years ago, 
which had been coated apparently by Smith's process, about half the 
interior surface of the pipe was covered with numbers of nodules or car- 
buncles of iron rust, varying in size from about i inch up to about li 
inches in diameter, and projecting into the pipe from about i inch to | 
inch ; in many plaoes these nodules had formed in clusters, and, as it 
were, had grown together, forming little patches of incrustation. The 
removal of these by the scraper left the surface of the pipe apparently in 
nearly as good condition as it was originally, with the exception that where 
each nodule or patch of incrustation had commenced to form, it could 
be plainly seen that the process of decay had commenced, the rust hav- 
ing eaten through the coating only in small spots, like pin-holes, leaving 
the great bulk of it in its original condition. 



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147 

With xeferenoe to an amdjsis of the water, I regret that I cannot give 
jon as fall information as I would wish. Although the low service 
water has been caref nlly tested on different occasions, I am not at libertj 
to publish the most full analysis that has been made, and the high 
service water has never, to my knowledge, been subjected to any com- 
plete or careful chemical tests. 

A sample of water taken from the middle of Long Lake, in September, 
1878, and analyzed by Professor George Lawson, of Dalhousie CoUege, 
Halifax, yielded 

Inorganic matter 1 * 71 grains per gallon. 

Organic " 2.13 " •• 

Total 8-84 *• *« 

Another sample taken on the same date from the inlet to the city at 
Lower Chain Lake, yielded 

Inorganic matter 2'44 grains per gallon. 

Organic ** 268 " " 

Total 512 «« •« 

The following additional extracts from the report of Professor Lawson 
may be of interest : 

« The iporganic matter consisted principally of alumina and iron, 
with silica (soluble), common salt, and a mere trace of lime. The 
water belongs to the class of soft waters, such as are collected in dis- 
tricts where there are no chalk or limestone strata, or other rocks capa- 
ble of yielding soluble substances." 

" It is obvious that the excess of impurity is taken up by the water 
in its course from Long Lake, through the Ghain Lakes, to the city 
inlet 

" The source of the impurity was discovered in upper Ghain Lake in 
the form of a deposit of a very peculiar character, in the bed of the lake. 
It extends apparently over the greater portion of the lake bottom, and is 
of a thickness so great that in several places a long crow bar almost dis- 
appeared in it without reaching bottom. The substance of this deposit 
varied in consistence from that of soft cheese to common baker's bread ; 
it varied in color from whitish or light skin color to dark ferruginous 
brown, some pieces being nearly black. It consists, to a very large ex- 



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148 

tent, of the remains of microscopic organisms belonging to the class 
called Infusoria. The following chemical analysis will show the com- 
position of the substance : 

<< Deposits fboh Bed of Uppbb Chain Lake. 

'• Sample No. 1 (pale brown, slightly ferruginous). 

Total amount of Inorganic Matter (buff-colored ash) 49 . 76 

Insoluble in hydrochloric acid (silicious infusorial earth, 

etc) 38.40 

Soluble in hydrochloric acid (Iron Alumina, etc.) ... 11.36 

Organic Matter. 11.32 

Water 38.92 

100.00 
•* Sample No. 2 (pale whitish skin-colored). 

Total Inorganic Matter (delicate skin-colored ash) 48.40 

Insoluble in HOI 38.96 

Soluble in ** 9.44 

Organic Matter 9.60 

Water 42 . 00 

100.00 
** Sample No. 3 (Intermediate in color, between Nos. 1 and 2). 

Total Inorganic Matter 49.20 

Insoluble in HOI 38.16 . 

Soluble in ** 11.04 

Organic Matter 8.72 

Water 42.08 



100.00 
*• Sample No. 4 (dark ferruginous brown, hygroscopic, not drying in air 
like the others). 

Total Inorganic Matter 24.70 

Organic Matter 11 .85 

Water 63.45 

100.00 



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149 

*' The depodt has, no doabt, originally dbnsisted of swamp muok, 
formed bj the remains of plants, infusoria, &o., bnt bj long subjection 
to the action of water passing over it has lost much of its organic matter. 
In the first three samples, which are of light color, and dry up like bread 
when exposed to the air, the organic matter (after deduction of water) 
amounts to about 16 per ceni, whereas in the sample No. 4, which is of 
dark color, and remains wet, the proportion is nearly 32 per ceni, just 
doubla The process of gradual washing out of the soluble organic mat- 
ter from the deposit, by the water of the lake, is well illustrated by the 
light color on the surface where it is in contact with the water, and the 
dark color beneath, seen when the upper layer is removed. 

« It may be added that a few specimens of fresh water spnoge {spon- 
gilla), (whose decay gives a very offensive odor to water), were found in 
upper Ghain Lake, but neither there, nor in the other lakes, were any of 
the plants found which are commonly known to render water noxious. 
In Spruce Hill Lake the surface of the water was, in many places, especi- 
ally near the shore, of a brilliant green color^ from the growth of a 
microscopic alg^ called Trichormus Flos-aquce, which has been observed 
to give a green color to the water in the Grand Canal Dock at Dublin, 
and has been observed also in Scotland, France, Wales, Germany and 
Finland. It is not known to be injurious, but is regarded as an indica- 
tion of water being stagnant or containing organic matter." 

I might add to this report of Professor Lawson that some of the im- 
purity is, no doubt, due to the circumstance that a public road which is 
much frequented skirts along the shores of the Chain Lakes for about 
a mile, and that the drainage is directly into the lakes just above the 
inlet. 

It should be borne in mind that the above samples of water were taken 
from the lakes in the autumn, when they were at a lower level than they 
have ever been known to reach before or since, and as the Chain Lakes 
are shallow and boggy ponds, it is inferred that the analysis given shows 
a greater amount of impurity than the water would be found to contain 
when in its normal condition* 

An analysis made from some water taken from a tap in the city (sup« 
plied from the low service) in the autumn of 1873 yielded : 

Total solids, less than 2 grains to the gallon. 

Organic Matter, very small. 



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150 

Professor Lawson states in his report that the inorganic matter con- 
4Edsted principally of alumina and iron, with silica (soluble), common salt 
and a mere trace of lime. It is owing to the absence of lime in the water 
that the rapid formation of oxide of iron in the pipes is attributed. 

The following circumstance will show how rapid this formation is 
when the water is brought in contact with unprotected iron. 

Four years ago a private citizen laid about 400 feet of ordinary 
wrought-iron one-inch gas piping (unprotected) for the purpose of con- 
ducting the water to his dwelling. The whole length of this pipe is now 
-completely filled with iron rust so that no water will pass through ii 



AMEEIOAN SOCIETY OF CIVIL ENGINEERS. 

INSTITUTED 1862. 



TRA.]SrS^OTIO]SrS. 

NoTB.^'i'hu Society is not rocponsible, as a body, for the facts and opinions advanced in 
any of its publications. 



CCXXXVI, 

Vol XI.-AprU. 1882. 



ON THE MODE OP UNDERPINNING ADOPTED FOR 
THE CROTON LAKE BRIDGE, N. Y. 0. & N. R. R., 
DURING THE REPAIRS TO THE MA- 
SONRY PIERS. 



By Alfred P. Bolleb, Member A S. 0. E. 



Read Apbil 5th, 1882. 



Inasmaoh as methods of doing work are as instructiye as a stndj of 
work accomplished, the writer offers to the Society an experience of his 
own, which may be suggestive to others when called upon to meet simi- 
lar problems. The Croton Lake Bridge was built by the writer during 



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151 

the summer of 1879 for the New York City and Northern Railroad Com- 
pany, its general features being illustrated, so far as the purposes of 
this paper are concerned, on the accompanying Plate Y. It is a single 
track wronght-iron deck structure, in three ^pans of 160 feet, with 
skeleton piers or towers springing from blocks of masonry, as shown. 
The towers have four legs, und therefore concentrate all weight on the 
four comers of the masonry. This masonry had 'been put in some ten 
years before by the bankrupt New York, Boston and Montreal Company, 
and was tested at the time the iron bridge was built by loading with 
stone in cribs, without showing any improper settlement. While this 
answei^ to test the foundations as a mass, it did not represent the con- 
ditions of weight to be delivered to the masonry, as events afterwards 
disclosed. The proper way would have been to have tested with rail- 
road bars, the weight of which it would have been easy to concentrate 
npon the area to be occupied by the shoes of the proposed tower legs ; 
but such bars being unavailable, the former mode was resorted to. The 
blocks of masonry were supported on timber cribs made of plank, car- 
ried up to low water, with an outside protection of rip-rap, as shown. 
The masonry itself was very suspicious looking, being built with stones 
set up on edge, with an indescribable bond, and generous joints, well 
pointed. The needs of expedition and the shrinking of the controlling 
powers from the great cost of rebuilding them, settled the question of 
their use as they stood, and the erection of the iron work proceeded. 
It was not many months after the bridge was in use before the masonry 
disclosed its real character ; the pedestal stones became cracked, and the 
bond at the comers commenced to separate. It was an ugly piece of 
business, and it was a long process of evolution before the writer de- 
vised the plan which was successfully carried out. Staging the whole 
of two spans, the water being 28 and 30 feet deep, was an expense not to 
be thou^t of, and it would have cost about as much to have straddled 
the piers, outside of the rip-rap, with wooden piers and trussed across 
the interval. The outcome of the study is well illustrated on the adjoin- 
ing plate. The wrought iron towers being a continuous piece of frame- 
work from shoe to cap, it was determined to build an inside wooden 
tower, with all parts in pairs, so as not to interfere with or require any 
removal of braces or stmts. This subsidiary tower being built with legs 
plumb, brought the points of support considerably within those of the 
iron legs. The bottom sills were so placed as to permit the introduc- 



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152 

tion of eight 20-ton hydraoho jacks, bearing against sill pieces on the 
masonry. Fortunately the timber cribs afforded sufficient room on the 
outer edges to build solid timber supports. This was done, and 15* —200 
lbs. per yard rolled beams were placed in pairs as shown, reaching on the 
inner side as far back as possible on the masonry, and the pressure well 
distributed with timbers. Two minutes work on the jacks served to 
lift the towers and adjoining spans bodily, when the defective masonry 
was racked out The wrought iron saddles and suspension bolts were then 
attached, the whole weight transferred to them, and the structure was 
ready for traffic again, while the new cut work was being put in. While 
the drawing shows both sides so arranged, only one side of a i^er was 
racked out at a time. As an additional precaution to lateral movement 
on such a high structure, wire rope guys were thrown out from the end 
shoes of the trusses and tower caps, and anchored to cribs sunk for the 
purpose. It is gratifying to state that the who>''"*' • ig^ment worked so 
perfectly that not a single train was delavr m its schedule time, and 
that a halMiour proved ample to raisf" .aiB structure, lack out a 
clearance in the masonry, and m: ail attachments for throwing the 
weight on the iron cross girders. In this connection I desire to make 
mention of my foreman, Mr. Wm. H. Clough, through whose skill and 
careful supervision I was enabled to accomplish so perfectly one of the most 
satisfactory pieces of engineering work that has fallen to my lot to per- 
form. Before closing this brief account of a temporary construction, 
the disclosures of those old piers is a story worth telling, and of all de- 
liberate, studied, cold-blooded frauds, those piers are entitled to the 
highest rank, and should consign to infamy all parties concerned in 
their creation. They were nothing but the merest veneer, of stones 
set up on edge, with no cement detectable internally, and filled up with 
sand, stones and rubbish, an occasional barrel head, and a plentiful sup- 
ply of engineers stakes, to " level up with." Many of the coping stones 
were actually out cross-g^ned, and no expense was apparently 
spared in doing everything wrong. Such instances of cold-blooded 
criminality almost restore any waning faith one may have in a hot im- 
mortality. 



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PLATE V 

TRANS.AM.SOC.CiV'. EXGRS. 

VOL. XI N9CCXXXVI. 

BOU-ER C^' 

UNDBRPINNIU . "^ ^E . 





Tj- Tjjr 




^ 



'U In i 



rs 



)DE OF UNDERPINNING, ADOPTED FOR 
OTON LAKE BRI DGE, N.Y.C^ N.R.R. 
!rINC RERAIRSTO masonry PIERS 

BY ALFRED P.BOLLER C.E. 



\ 



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AMEMOAN SOCIETY OF OIVIL ENGINEERS. 

INSTITUTED 1862. 



TRA-isrs^OTioisrs. 

NoTK.— This Society la not responsible, as a body, for the facts and opinions adTanced 
in any of its publications. 



CCXXXVII, 

(Vol. XI.— May, 1882.) 



ADDRESS 

OP 

ASHBEL WELCH, President, A. S. C. E., 

At the Annual Convention op the SocTBTy, at Washington, D. C, 

Mat 16. 1882. 



I do not propose this evening to undertake any general survey of the 
engineering field. For such a survey, I xeter you back to Mr. Chanute*s 
address of two years ago. I shall not attempt to glean after him. But 
I shall speak of several disconnected subjects of present interest, and 
give some reminiscences showing the contrasts between the past and 
the present ; and in such reminiscences I shall disinter the buried 
memories of some of the great engineers of the past. 

When we look around on the engineering works recently completed, 



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154 

or now in progress or in contemplation, the first thing that strikes as is 
their extraordinary magnitude. 

Prominent among them is the St. Gothard Tunnel, passing for 48 900 
feet, or more than nine and a quarter miles^ through the base of the 
great Alpine chain which has hitherto been so formidable a barrier be- 
tween soathern and central Europe, a thousand feet below the yale of 
Urseren and the villages of Andermatt and Hospenthal, and 6 500 feet, 
or a mile and a quarter below the eternal snows that cover the crest of 
the mountain. The cost was about $12 000 000 ; or nearly $250 per foot 
lineal. This tunnel is nearly 9 000 feet, or a mile and two thirds longer 
than the Mt. Genis tunnel, by far the longest previously built. 

Such stupendous works have been made practically possible by the 
compressed air drill, and the high explosives now used. In my active 
engineering days, rocks were drilled for blasting only by the power of 
human muscle, either by one or two men churning a hole in the rock 
with a heavy rod some six feet long, or by one man holding and slowly 
turning a short drill, and another man driving it into the rock with a 
sledge hammer. Then came the steam rock drill, then the compressed 
air drill. The compressed air not only does the work, but it ventilates, 
and its sudden expansion cools, the tunnel or the mine where it is used. 

The first, or one of the first tunnels in this country in which the rock 
was drilled by compressed air, was the Nesquehoning, by Mr. J. Dutton 
Steele. Since then many have been made by the same means, one of the 
most memorable of which is the Musconetcong tunnel, a mile long, 
made under the direction of Mr. Robert H. Sayre. This difficult work gave 
occasion for the valuable treatise on tunnels by Mr. Drinker, who was in 
immediate engineering charge of it. The Hoosac Tunnel, 24 000 feet 
long, after a long-continued struggle, was completed several years ago, 
and is now in use. 

Among the tunnels now being constructed, is one half a mile long 
under the plateau of West Point ; and another 4 000 feet long through 
the hard trap rock of Bergen Bidge, at Weehawken ; both on the line of 
the road now in construction on the west shore of the Hudson. Nearly 
all the debris from the latter is raised through shafts. 

The project is now under serious consideration of making a tunnel 
some 21 miles long under the straits of Dover. A few years ago such a 
project would have received only a laugh of incredulity. 

The admiration of the world has not yet abated for the boldest of 
arched bridges yet built, that over the Mississippi at St. Louis ; with its 



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155 

steel arches of 500 feet span, its piers of heavy masonry sunk to solid 
rock more than a hundred and thirty feet below the high water surface 
of the river, through shifting sands, and during the most fearful floods. 

The Brooklyn Bridge— 1 595 feet or nearly a third of a mile long, 
over an arm of the sea more crowded with commerce than any other in 
America, and high enough to allow a line of battle ship to sail under it — 
is drawing U> completion, and will be (though perhaps only for a few 
years, 'tiU something mofe stupendous comes), one of the wonders of 
the world. 

Probably the boldest plan for a bridge ever proposed, is that now in 
contemplation over the Forth, at Edinburgh, but of which it is yet pre- 
mature to speak. 

Many very long spans and important bridges are now in progress in 
this country, such as the one over the Missouri by Mr. Morrison, but 
time does not permit even a glance at them. 

We are- now so familiar with the success of suspension bridges for 
railroads, that we can hardly realize the almost universal disbelief in that 
success before they were tried. The late John A. Boebling told me be- 
fore his bridge was finished, that Bobert Stephenson had said to him, 
''If your bridge succeeds, mine is a magnificent blunder." And yet, 
unexpectedly to the best engineers in the world, the suspension bridge 
over the Niagara answers the purpose quite as well as the tubular bridge 
over the St. Lawrence. 

The mention of the St. Lawrence reminds us of the great and inter- 
esting improvement of that river now going on under the direction of 
Mr. Kennedy. The original low water channel between Quebec and 
Montreal, had, in places, a depth of only 11 feet. Now they are increas- 
ing the low water depth to 25 feet, with a width of 300 feet. The work 
is done with bucket and chain dredges, exceedingly well adapted to the 
purpose. Some of the buckets are armed with great steel teeth which 
excavate the solid rock (geologically Utica slate, but compact rather than 
slaty in its structure), detaching and bringing up blocks sometimes con- 
taining several cubic feet. 

If anything of the kind could astonish us in this fast moving age, it 
would be the rapidity with which, during the past half dozen years, the 
construction of elevated railroads in New York, and to some extent else- 
where, has gone on. It is of little use to find their aggregate length, for 
in a few weeks any such estimate must be corrected. There may now be 
about thirty -three miles of such roads, all double track. The average 



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156 

cost, including stations and equipment, has been about $800 00(^ per 
mile. 

One of the cases in which a new contrivance effects a great revolution, 
is that of the elevator. This has been in use for perhaps a quarter of a 
century at the Continental Hotel in Philadelphia, and in a few other 
places, but is now coming into general use, and is revolutionizing the 
mode of building in our great cities, especially in New York. A block 
of buildings is not now extended along a street as formerly, but is 
set up on end, and the highway to the different houses or parts of the 
block, is not horizontally along the sidewalk, but vertically through the 
elevator shaft. Sky room is cheaper than earth room. It is said that a 
lot on the corner of Wall and Broad streets was recently sold for over 
$320 per square foot, or at the rate of $14 000 000 per acre ! Equal to 
the surface covered with silver dollars 5 deep. These stupendous build- 
ings will give engineers and architects much to look after in the way of 
foundations. 

This reminds us of the Holly plan, in limited use elsewhere for several 
years, now going into extensive use in the City of New York, of dispens- 
ing with private fires for heating, and private boilers for generating 
steam ; and furnishing heat and steam power for a considerable district 
from one great central set of boilers, piled boiler over boiler, tier on tier, 
for 120 feet in height. This is one of the operations most charactepstic 
of the present time. Nothing is to be done now by the individual, but 
everything by some institution, or corporation, or central power, or 
great firm. Man has ceased to be a unit, and become only an atom of a 
mass. With the disappearance of the things themselves, the dear old 
phrases *' family fireside," and *' domestic hearth," are rapidly disap- 
pearing. 

Mr. Shinn and the Engineer, Mr. Emery, have kindly given me some 
particulars respecting this transportation of heat and power, but I can only 
refer to one or two points. The first and most obvious necessity is to 
prevent the escape of the heat. This is done by enclosing the steam- 
carrying pipe in a small brick tunnel, with a flat cover on the top ; and 
filling the space around the pipe, from the bottom of the tunnel to the 
flat covering above, with mineral wool, which is found to be an ex- 
cellent non- conductor. It is made by blowing a jet of steam into a 
stream or jet of melted furnace slag. The arch and covering of the 
tunnel are plastered over with asphaltum, to exclude all moisture. 
The loss of heat is said to be very small. One of the great difficul- 



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157 

ides comes from the expansion and contraction of the pipes, the range 
beiiig more than an inch in a hundred feet This is provided for by 
making the end of each section of about 80 or 100 feet, terminate in 
▼erj flexible diaphragms of thin copper, the diaphragms being supported 
by stiff iron ribs. 

Among th& great enterprises in contemplation, is the interoceanic 
canal, or the interoceanic railroad for large ships. This is not the occa- 
sion for expressing any opinion on any of the competing projects. I 
will only say that if the world is determined to have a sea level canal, it 
makes a great mistake in not getting fuller information about the San 
Bias route. 

Many things that have been done by this generation seemed before- 
hand far less possible than the successful working of the ship railway 
proposed by Captain Eads. The difficulties are certainly very great, 
but we can see how they may be overcome. The real question is, 
whether, taking into account the expense of overcoming those difficul- 
ties, the construction and operation of such railway will be more 
economical in the end than the construction and operation of some one 
of the proposed canals. 

The last year has been one of intense activity, particularly in railroad 
construction. A year or two ago money was so abundant, and, there- 
fore, interest so low, and so many capitalists, great and small, were 
tired of letting their money lie idle, that new enterprises of many kinds 
were started, especially new railroads, and enlargements of capacity 
of those already in use. As the money market has approached its 
normal condition, some of the new projects have been dropped. ^ 

It is instructive to look back and trace the connection between the 
progress of railroads and the financial condition of the country. 

From the year 1787 there has been a financial catastrophe, or at least 
depression, in our country regularly every ten years down to the year 
1857. The cause of this seems to be rather psychological than anything 
else. It seems to have taken the American business mind just ten 
years to pass through the various stages and degrees of panic after the 
financial crash, through extreme cautiousness, great cautiousness, mod- 
erate cautiousness, moderate confidence, great confidence, extreme con- 
fidence, recklessness, and then another crash. 

These decennial depressions were modified by circumstances. That 
of 1817 was intensified by the effects of the war of 1812 and by the 
failure of the crops of 1816. That of 1837 was moderated by the efforts 



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158 

of the United States Bank, and part of its effects postponed nntil the 
final failure of the bank a few years later, which produced the inter- 
calary depression of 1842. The effects of the crash of 1847 were mod- 
erated within two or three years by the discovery of the gold in California. * 
The crash of 1857 was intensified by the previous infiation from the 
gold excitement, the rapid railroad construction in the West stimulated 
by the land grants, and its effect continued longer than usual on 
account, first, of the apprehension, and then the reality of civil war. 

The effects of a financial crash do not appear in the statistics of rail- 
road construction till a year or two after it takes place, for if a road is 
well advanced towards completion, it will probably soon be finished, 
even during a panic. This is shown in the statement following. 

In consequence of the financial troubles of 1841-2 the mileage of 
new railroads opened in 1843 and 1844 fell off 71 per cent, below that 
of the two preceding years. Before the panic of 1847 had time to 
reduce the increase of mileage its effects were more than counterbalanced 
by the discovery of gold in California and by the land grants. After 
the great crash of 1857 the new mileage in 1859 and 1860 fell off 57 per 
cent, below the average of the three preceding years. 

During the four years of the war the new mileage was 64 per cent, 
less than that of the four preceding or of the four succeeding years. 

Notwithstanding the excitement and inflation after the close of the 
war, the periodicity of the financial intermittant was broken, and no 
crash occurred in 1867. The causes are too recent and too well known 
to require mention. Besides the infiux of money from the sale of our 
goyernment bonds abroad, the ocean telegraph hastened the equaliza- 
tion of interest on both sides of the Atlantic, and the fiow of money to 
the points where it was wanted. A few years ago the normal rate of 
interest in the West was 50 per cent, higher than in the East. Now 
there is but little difference. The depression was postponed till 1873. 

From the close of 1867 till the close of 1874, when the effects of the 
panic of 1873 became visible in the statistics of railroad extension, 
more than 4 400 miles of railroad per annum were opened, twice as 
much as the yearly average of any similar period had been before. 
For the next three years (1875, '6 and 7) the annual increase fell off 
69 per cent, below the average of the preceding seven years. 



* That ditoovery was first made in digging the foundation or the tail race of Sntor'a Mill, 
by James W. Marshall, who fifteen years before had been a boss on work going on under 
nvy direction, and whose three sisters are still neighbors of mine. 



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159 

The troubles that followed the panic of 1873 were entirely different 
from those that followed any of the decennial or other panics previons 
to that time. They were financial ; this was commercial. In all the 
earlier cases the difficnlty was want of money, in this last case there 
was, or soon came to be, a plethora of money. Those were convulsions, 
this was stagnation. There were more means of production and of 
transportation than there was demand for. If wealth consists of such 
means, then the community were sufifering from excess of wealth. 

The railroads opened in the United States January 1, 1880, aggregate 
86 500 miles in length, being 40 per cent, of all the railaoad mileage 
of the world. Last year we had 93 600 miles, and this year we have 
just about 100 000 miles. Bat mere length is a very inadequate measure 
of their magnitude. The terminal mile of some roads has probably 
cost as much as Ave hundred miles of some other roads. At one time, 
and possibly now, the cost per ton taken, on the first two miles of the 
road from New York to Pittsburg, was more than the cost of carrying that 
ton over the next two hundred miles. The increase in aggregate mag- 
nitude of all the roads may be almost as much in the enlargement with- 
out increase in length of the old, as in the extension of the new. We 
hear in more than one case of thirty miles of additional terminal tracks 
being laid at one point. 

The diminished plethora of money, and the greater caution now 
apparent, wiU, it is to be hoped, moderate the increase of the means of 
production and transportation beyond the demands of consumption, so • 
as to prevent another stagnation. 

The investment in railroad property in the United States is set down 
at about 5 000 millions, perhaps about one-eighth of the value of all 
the property of the country, real and personal. 

When we speak of the extraordinary magnitude of the engineering 
works of the present day, we do not forget the pyramids, temples, and 
fortifications of Egypt and Ohaldea. Some of them exceeded in magni- 
tude anything that has been made since. What makes it more strange 
is, that the force that produced them was almost entirely human 
muscle, while now the work is done largely by steam directed by human 
brain. Two contrasts strike us as we look at the ancient and modem : 
the one was execated by slaves and conscripts, with little or no compen- 
sation ; the other by free men, glad to work for the compensation 
offered. The old was for the glorification of the few ; the modem for 
the use of the many. 



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The stagnation that followed the breakdown of 1873, and the conse- 
quent low rates of transportation, compelled the managers of railroads 
to reduce the cost to a point previously thought unattainable, by 
increasing the power of the engines and the weight of the trains, by 
more convenient arrangements, by more service of the machinery, by 
cheaper construction and repairs, by better machinery and organizations 
of labor, and many improved appliances for handling, and by the stop- 
page of leaks generally. 

American engineers and managers have often shown that poverty is 
the mother of invention. For example, they used cross ties as a tem- 
porary substitute because too poor to buy stone blocks, and so made 
good roads because they were not rich enough to make bad ones. 
American engineers are, or at any rate, were trained on short allow- 
ance of money. As that is the best engineering which accomplishes the 
purpose at the least cost in the long run, American engineering ought 
to be of the best. 

It is doubtless the fertility of resource coming from the necessity of 
effecting much with little means, which has created a demand for Amer- 
ican engineers in other parts of the world. A few years ago the 
Government of British India sent for an American engineer, and the 
first thing they asked him to do was to report on their railroads from 
the American point of view. Our lamented past president, W. Milnor 
Boberts, was employed by the Government of Brazil, as I judge from 
what happened after he went there, to train their engineers, educated 
in European schools, in American modes and ideas. 

Among the greatest of the projects of the present day is the improve- 
ment of the Mississippi Biver. 

Towards it the eyes of our profession and of the whole country have 
of late been anxiously turned. It has overflowed an extent of territory 
of more than 20 000 square miles, and destroyed millions on millions of 
property and hundreds on hundreds of lives. One of the most impor- 
tant engineering problems of the age is how to restrain its ravages, as 
well as to improve its navigation. 

In order better to understand what the Mississippi Biver Commission 
is doing for these purposes, let us glance at a few of the principles 
which, or some of which, doubtless control the action of that commis- 
sion. Those principles are very simple, though their application is often 
very difficult. 

The quantity of solid matter of greater specific gravity than water 



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that a ranning stream is capable of oarrying in saspension, other things 
remaining equal, increases with the increase, and decreases with the de- 
crease, of the velocitj of the stream. Like most cardinal principles, this 
is so simple and obyioos that it seems ridiculous to state it. 

It follows, from this, that when a stream is loaded with such matter 
up to its carrying capacity, then, other things remaining the same, if the 
velocity is decreased, it will drop part of its load, and if the velocity is 
increased, it will, if suitable material is in contact with the current, take 
on more load, 

Mathematicians have calculated that the difference in velocity be- 
tween parallel films of moving water keep the particles of solid matter 
afloat ; but, as is obvious to the eye, and as Mr. Francis has proved, 
running water does not move in parallel films, and it is also obvious to 
the eye that the suspended matter commonly moves more or less up and 
down. The real motion is a compound of parallel and ricochet move- 
ments, combined in all sorts of ways and proportions, the boiling and 
plunging movements increasing with the velocity, the unevenness of the 
bottom and sides of the channel, and the presence of foreign objects 
and aquatic vegetation, and being greater in proportion to the whole vol- 
ume of the water when that is shallow. It is largely this boiling move- 
ment which raises the solid matter and keeps it afloat. With the same 
velocity, the greater it is, the greater the capacity of the stream to carry 
such matter. Some of the causes, however, which produce the boiling 
motion may diminish the velocity, and so, on the whole, diminish the 
transporting capacity.* 

This is one reason why the exact relation between velocity and trans- 
porting capacity is so diflScult to determine. 

The same current will raise and carry a greater weight of small than 
of larger particles of the same form and material ; for the impact of the 
current against the particle, tending to move it, is as its surface, that is, 
as the square of its linear dimensions, while the weight and consequent re- 
sistance to motion is as the cube of the same dimensions. Flat particles 
are carried more easily than round or cubical, for they have more surface 
in proportion to weight Of course a particle of greater specific gravity, 
as of trap rock, is harder to move than one of the same form and size of 
less specific gravity, as anthracite. It takes eight times the force to raise 
a particle of specific gravity 3, in water, that it does to raise one of the 
same size of specific gravity 1^. This shows why, in many cases, a 
higher velocity carries no more weight of solid matter per cubic foot of 



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water than a lower ; the higher velocity and greater boil take up larger 
and heavier particles than the lower, and a much larger amount of 
transporting capacity is used up in carrying them than in carrying an 
equal weight of finer and lighter particles. 

This is another reason why the exact relation between velocity and 
transporting capacity has not been ascertained ; the sizes and specific 
gravity of the particles transported are not known, and therefore their 
efifect on total quantity transported is not known. 

This relation might perhaps be found by some such experiments as 
the following : Ist. Grind some suitable kind of stone of uniform substance 
to fine powder ; then, by sifting, separate the partibles of the powder 
or dust into lots according to size, each of uniform fineness ; then see 
how much weight of each of these sizes per cubic foot of water can be 
carried in suspension at the same velocity. 2(1. Make the same experi- 
ment with stone of different specific gravity, sortiug it into lots of the 
same sizes, the water being kept at the same velocity. 3d. Try the same 
things with different velocities. The facilties for doing all this can 
probably be found at some cement mill. 

The specific gravity of the bank furnishing the silt, or of the bar 
formed by it, or of the sediment deposited from the water, gives no 
information of the size of the particles, and little of their specific grav- 
ity. Hence the transporting power with the same velocity appears so 
different in different observations. Total weight gives only partial infor- 
mation. 

I should expect that the transporting power would be as the square 
of the velocity. I have washed out bars of heavy sand by temporarily 
confining the current over them, and its power of removing the sand 
seemed to be about as the difference in level of the water above and 
below, that is, as the square of the velocity created by that difference. 

Though the weight of solid matter per cubic foot of water carried 
near the bottom is often but little more than near the surface, it is com- 
monly much coarser, and therefore uses up much more transporting ca- 
pacity. The velocity near the bottom is also less. From each of these 
circumstances, especially from both together, it follows that the trans- 
porting capacity is much greater near the bottom, where the boiling mo- 
tion is greatest, and where the difference in the velocity of the films of 
water is the greatest, than near the Eurface. 

It is sometimes said that the transporting capacity with any given 
velocity is inversely as the depth. This cannot be so, for it would lead to 



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the absurd oonclusion that, with the same velocity, a stream a foot deep 
is capable of carrying as much silt in the aggregate as a stream a hundred 
feet deep. 

If a stream runs over a soft uniform bed for a sufficient length of 
time, it will become dharged with the maximum quantity of solid matter 
due to its velocity, its depth, its boil, and to the size, shape and specific 
gravity of the particles taken up by its current. If there is not suitable 
material within reach of its current, it will carry less than its maximum. 
As before pointed out, aggregate weight of silt alone is a very imperfect 
measure of transporting capacity. The maximum load with the same 
velocity may perhaps be two or three times as great with one material as 
with another. 

If a stream carrying its maximum quantity of silt widens as you go 
down stream, so that, when the water is high, its section becomes 
greater than that of the stream above, the velocity decreases there, and a 
deposit takes place. The coarsest particles will drop first, and thus the 
bar formed is likely to be hard. When the water subsides, so that the 
area over the bar becomes less than that of the deeper water up-stream, 
the dedivity of the surface must be increased in order to get the in- 
creased velocity necessary to pass the water through the smaller area, 
and that raises the surface above the bar, deadens the current up-stream, 
and causes a deposit to take place in the deeper water above. Thus the 
tendency of expansions of a stream beyond its normal width is to raise its 
bottom not only there, but everywhere, and consequently to increase the 
height of its ^pods. 

If, on the other hand, a wider place is contracted to the normal 
width of the stream, the velocity will be increased so as to cut out the 
bar, if the material of which it is composed is not too hard. By making 
the channel of uniform width, and keeping it regular and even, the bed, 
if soft, will be lowered, and the height of floods diminished. With a 
given discharge, the greater the depth, the less is the fall required ; or, 
with the same &11, a less area. A memorable example of the deepening 
effect of the contraction of a stream to the regular width is by the South 
Pass Jetties. 

The tendency of the greater velocity to take up and carry off solid . 
material is illustrated at bends of rivers. The swiftest water is near the 
concave shore, that side of the channel is in consequence deepened and 
the more rapid current eats into that shore. The current on the convex 



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Bide is slackened and a deposit takes place. Hence a crooked stream 
has a constant tendency to become more crooked. 

It has always been a wonder why an eddy carrent was more erosive 
than a direct current. My theory is, that when the water turns from its 
direct course and curves round toward the shore, the centrifugal force 
separates and throws off a part of the coarser particles held in suspen- 
sion (just as in old times when a farmer threw a shovel full of mixed 
wheat and chaff, the heavier wheat went beyond the chaff), and thus the 
current being now deprived of part of its load, its power of erosion is 
partially restored, and it cuts the bank rapidly. 

The Mississippi Biver approximates the conditions of such a stream 
as I have described. 

The first thing done to improve it, is, to make its channel as uniform 
as possible by contracting its wide expanses. This is done by placing a 
continuous line of brush matresses or screens along each boundary of 
the modified channel, the edge of the mattress next the channel being 
sunk to the bottom with stone, the edge farthest from the channel being 
buoyed up to the surface of the water. The silt-bearing water filters 
slowly through the mattress, and the current being deadened, drops its 
sediment and soon forms a bank under and behind the mattress. This 
new bank is protected from erosion by the inclined face of the mattress. 
In floods, the current goes over the mattresses into the bays outside, 
where the velocity being slackened the silt is deposited, the bays are 
gradually filled up, and dry land ultimately forms between the line of 
the mattresses and the original shore. Confining the current increases 
the velocity and deepens the channel between the lines of the mattresses, 
a uniform channel is established, the bed of the stream is lowered, the 
water being deeper less declivity of surface is required, the water sur- 
face is lowered, and the overflow in floods moderated. 

When running water washes the foot of a vertical bank, suppose for 
example 60 feet high, and washes out a narrow groove along its face, 
suppose a foot deep, and then the overhanging mass falls so as to leave 
the bank still vertical, the quantity that falls into the stream is 60 cubic 
feet per foot lineal of the stream. The finer part of this will be carried 
down stream, the coarser will probably gradually work down to the bot- 
tom and raise the bed. Thus the capacity of the river will be diminished 
and the height of the surface and of the floods increased. But if the 
water of the same stream washes a foot horizontally into a bank sloped 
one to one, and the overhanging weight falls so as to leave the back of 



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the step thus made vertical, the quantity thus thrown into the stream 
will be only half a cubic foot per foot lineal. 

Hence the absolute necessitj of sloping the banks of the Mis- 
flissippi where they are steep and unprotected. The commission are 
forming this slope by the use of the water jet, and protecting it until 
the rootlets and willows cover and protect it, by a slight covering of 
brush. 

The great forces of nature, though they cannot be resisted, may often 
be guided and controlled by means that seem the feeblest. The ma- 
gician of science is to control the mighty Mississippi with the willow 
wand. 

If a stream of uniform section, bearing its maximum load of silt, and 
conftn^ within iU bcmks, is furnished with an additional channel, then 
though each channel may take its proportion of the silt brought down 
from above, the reduction of velocity consequent on the increased aggre- 
gate sectional area, will cause a deposit to take place below the bifur- 
cation, the bed of the original channel will be raised and its capacity 
diminished. Hence a bar is likely to form below an extensive crevasse. 

But if a stream overflow its banks, then the water that would other- 
wise run overland may be carried o£f by additional outlets, so that they 
do not lessen the velocity of the main stream, below the point of 
diversion. 

The principles that govern such cases are mostly plain enough, but 
owing to many disturbing circumstances, their application is often very 
difficult. A thousand cases may arise where opposing tendencies ope- 
rate, each tendency with imperfectly known force, about which no man 
can form an intelligent opinion without an intimate knowledge and 
careful study of the circumstances, and careful weighing of the force of 
the opposing tendencies. 

I have stated those principles and their application not because 
hydraulic engineers will find anything new in the statement, but to 
bring them to the attention of such dry land engineers as may not 
already have considered them. 

I think no apology necessary for dwelling so long on this subject, for 
there is no other so opportune, no other more important 

To this generation it seems almost ridiculous to mention turnpikes as 
ever having been of any interest. And yet the City of Philadelphia 
retained for a time its commercial ascendency by them, especially by the 
great Lancaster turnpike. If I rightly remember the language of the 



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geography I studied when a boy, it somewhat exoltinglj described this 
turnpike as^**aaTeuty-two miles long, four rods wide, and covered, wide 
enough for two wagons to pass, with eije^hteair moLuLoi pounded stone." 
It was over this highway that the wealth of the interior poured mtD^ ttia 
<^mmercial metropolis of America, in Oonestoga wagons. 

The National roads from Washington and Baltimore into Ohio, made 
by the Federal Goyernment are famous for their share in settling some 
of the important constitutional questions of our government. One 
great party disputed the power of Congress to use the nation's money 
for any such purpose. The contest was long and fierce, but Congress, 
with much misgiving, made the appropriations. When a few years ago 
they appropriated 315,000 for the improvement of the Eiskiminitas, 
they must have got bravely over such misgiving. 

Though canal engineering is a thing of the past, its history is in- 
structive. In England it commenced 120 years ago, the first engineer 
being James Brindley, a millwright He seems to have known little of 
what had been done before, and his plans were evidently original. When 
he proposed to build an aqueduct across the Irwell for the Duke of 
Bridgewater*8 canal, his critics said they had often heard of castles in 
the air, but they never heard before where they were to be put 
Brindley built several canals, on one of which was a tunnel a mile and a 
third in length. He was succeeded in canal making by such men as 
'Telford and Smeaton and Bennie. Though uneducated, he gained the 
admiration of scientific as well as practical men. When he wished to 
study a subject thoroughly, he "laid in bed to contrive," as he ex- 
pressed it The secret of his success, therefore, evidently lay in concen- 
tration of attention on the subject in hand, and he kept out of the way 
of anything that could distract his attention. 

The era of canal building in England was rather less than seventy 
years ; between 1760 and 1830. 

During the last decade of the last century, several efforts were made 
to connect the detached navigable reaches of some of the rivers in this 
country, by means of short canals and locks. One of those was under- 
taken at Bichmond under the inspiration of General Washington. 
Another was at Philadelphia, around the Falls of the Schuylkill. But 
the one of special interest in the history of engineering, was at Little 
Falls on the Mohawk. 

The great thoroughfare between the City of New York and the West 
and Northwest was up the Hudson and through the valley of the 



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Mohawk. The transportation through that valley was partly by three, 
five, or seven-horse teams over the Genesee Turnpike,* and partly by 
boats on the river. Those boats were like what on the Delaware we used 
to call Durham boats, which were 8 feet wide and 60 feet long, drawing, 
when loaded, a foot or two, and carrying from 10 to 20 tons. They were 
pushed up stream by two or four men with setting poles held against 
the shoulder, and kept in their course by the captain with a long steer- 
ing oar. 

At Little Falls the descent of the river is over forty feet, and, of 
course, the boats could not pass, but their cargo was carried by the 
portage of two miles, to other boats above or below. To avoid this the 
canal and locks were built They were finished in 1794. Jedediah Morse 
(father of S. F. 6. Morse, of telegraphic fame) published his great 
standard American Gazetteer a few years later, and in it he quotes the 
following expression of the public scQtiment of the time : ''The opening 
of this navigation is a vast acquisition to the commerce of this State.*' 
It was conjectured that these locks (which a man could almost jump 
across), and similar '* great works " west of them, might soon make the 
little town of Albany the capital of a great empire. 

The Mohawk continued to be the principal artery of commerce from 
New York to the interior, until the opening of the Erie Canal in 1825. 

Mr. Weston, "that haughty British engineer," a^an old gazetteer 
calls him, was brought over from England to build the locks at Little 
Fails and elsewhere. One of his assistants was a land surveyor of Rome, 
New York, named Benjamin Wright, or Judge Wright, as he was called. 
When, years afterwards, it was decided to build the Erie Canal, Judge 
Wright, though having only the slender experience he had acquired un- 
der Weston, was appointed chief engineer. The skill and good judg- 
ment which was shown by this father of American engineering, the few 
errors into which he and his still more inexperienced assistants fell, the 
great effects produced by them with the means at tbeir command, and 
the adaptation of their works to the circumstances of the time, are abso- 
lutely wonderful. 

One of Judge Wright's principal assistants was Canvass White. His 
skill early brought him into notice, and he was sent by the State of New 
York to England to learn what he could, especially about hydraulic 



■ * The migration to the West (which then meant the Qenesee country) was over this turn- 
pike in horse or ox teams ; the patriarch of the family and his wife having on their shoitlders 
the same black and white coverlet, and the big brass kettle full of dishes hanging under the 
hinder axletree of the wagon. Some of their grandchildren now sit in the high places of the 
naUon. 



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cement. Despairing of getting it at any reasonable price, and of making 
it stand the voyage, then from four to ten weeks, he set himself on his 
return to finding or making a substitute for European cement. 

Led partially by the geological position of the hydraulic limes in 
England, and partly by what was known of their compositiqp, he ex- 
plored and tested certain rocks of Western New York, and made the first 
discovery of hydraulic cement in America. The State of New York 
gave him ten thousand dollars for his discovery. Subsequently he dis- 
covered or recognized cement rock in Pennsylvania in the way till then 
unknown, but now so familiar, by the contact of limestone and slate. 

And yet how soon those men, once so widely known, are forgotten. 
An eminent and excellent engineer, who had paid especial attention to 
cement, lately told me he never heard of Canvass White. 

One of Judge Wright's assistants, but much younger than Canvass 
White, was John B. Jervis, whose name to-day is one of the most hon- 
ored on the rolls of this society. 

Many of the distinctive characteristics of American engineering 
originated with those Erie canal engineers. We practice their methods 
to-day, though most of their very names are forgotten. As a class, they 
wrote little. There were then no engineering papers prepared, and no 
engineering societies to perpetuate them, if they had been prepared. 
They were not scientific men, but knew by intuition what other men 
knew by calculation. Judge Wright's counsel was *' as if a man had in- 
quired at the oracle of God." What science they had, they knew well 
how to apply to the best advantage. Few men have ever accomplished 
so much with so little means. 

The mention of cement reminds us of quite a new use of it, lately, 
under the direction of Mr. Chanute. The Erie road crosses the Genesee 
river by a high viaduct just above afalL The bed of the river was wear- 
ing away, and would soon destroy the viaduct. An artificial bottom of 
cement has stopped the wear. 

The Erie canal was opened in 1826. Gov. Clinton passed through in 
a boat on one corner of the deck of which stood a cask of water from 
Lake Erie, on another corner a cask of water of the Hudson. Gov. 
CUnton limped from the boat to the public haUs, and speeches were made 
by and to him ; and it was a great glorification. The result justified 
the public expectation. It built up the City of New York, and settled 



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the question of commercial supremacy between that city and Phila- 
delphia.* 

The success of the Erie canal soon brought about the construction of 
many others. They were thought to afford the most economical means 
of transportation, and railroads were made, not to carry goods to the 
final destination, but to a canal or other navigation. After the success 
of the Liverpool and Manchester Railway in 1830, this opinion was 
seriously shaken, and in a short time canal construction mostly ceased. 
Its era in this country was scarcely a quarter of a century, between 1817 
and 1835. 

Canals to be successful now must be capable of passing vessels of 
large capacity, must not have too much lockage, and the locks must be 
worked by steam or water power ; the boats must be moved by steam, 
either on board, when the vessels are large enough, or, when the vessels 
are smaller, by locomotive on the bank, or by cable at the bottom, and 
then the locks must be large enough to hold the fleet taken by one loco- 
motive or cable tower ; there must be plenty of water, and the canal 
must connect harbors or navigable waters. 

I tried towing by locomotive on the canal bank more than forty 
years ago. There is, of course, no difficulty in one engine towing sev- 
eral boats, but if the locks are not largs enough to pass the whole fleet 
at once, the delay of all the fleet till each boat is passed separately, coun- 
terbalances the economy of steam instead of horse power. The speed 
even for light boats cannot be increased to more than five or six miles 
per hour on account of the wave. 

Cable towing, nofcwithstanding the reported failure on the Erie 
canal, can, with proper boats and apparatus, and with experienced men, 
be easily performed on the crookedest canal in America, as it is now 
done in Belgium. 

Canal engineering does not avail itself of the engineering resources 
of the age. Little improvement is made in it : mainly, I suppose, be- 
cause it is not considered worth improving. 

The most remarkable early river improvement in this country was 
that of the Lehigh. 

About the year 1817, Josiah White and Erskine Hazard commenced 
the improvement of this river, and made other preparations to inaugu- 
rate the anthracite coal trade. In 1820 they sent to market 365 tons, 

*kn old pilot once told me that in his yonnger days there were three or four ships out of 
Philadelphia to one out of New York. 



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which was the beginning of the regular anthracite coal trade of America. 
Now the annual amount will soon reach 30,000,000 of tons. 

The descending navigation thej made consisted, first, in clearing the 
ohannel of rocks, and confining the water in the rapids, when low, to 
that narrow channel by boulder wing dams ; second, when the fall was 
too great for this, in building dams with bear trap locks ; and third, in 
storing the water in pools, and letting it run only when the coal arks 
were running. 

The bear-trap locks have given the hint for several devices since used, 
and are well worthy of examination. Near each end of the lock was a 
pair of gates, each gate reaching across the lock and to the back of the 
recess on each side, which gates, when not damming back the water, lay 
flat on the bottom of the lock. The lower gate could be made to revolve 
through an arc of somewhere about 40 degrees around a horizontal axis 
coincident with its down-stream edge. The upper gate of the pair, when 
laid flat, lapped over about half of the width of the lower gate, and re- 
volved through a similar arc around its upstream edge. When laid flat, 
the water, of course, ran freely over them. They were raised by admit- 
ting the water under them from the pool above the head of the lock, 
through tbe side wall, when the pressure of water pressed them up. 
They were prevented from going too far by shoulders in the recesses. 
The gates then came within 10 or 15 degrees of being at right angles to 
each other, the under side of the upstream gate resting on the upstream 
edge of the downstream gate. They could be held in any position, so as 
to hold back the water entirely, or let it run over with more or less vol- 
ume, as required. The arks containing the coal were commonly shot 
through over the partly raised gates as over so many dams. 

Such locks, copied from those on the Lehigh, are now in use on the 
Ottawa, at the Canadian capital. Many of us at our last convention 
were shot through them on rafts. 

It is well worth inquiry whether these bear-trap gates would not be 
the best possible, and possibly the cheapest, for letting the water rapidly 
out of a reservoir for scouring purposes. A full stream could be set 
running in a few seconds, and the flow could be regulated with perfect 
ease, and stopped at any moment. 

In many rivers it is desirable to dam the stream back at low water, 
and let it run freely at high water. In Belgium, on the Meuse, they use 
needle dams for this purpose. Another probably better adjustable dam 
is in use in France. The bear trap gates, with proper appliances, on a 



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« 

solid platform at the bottom of a river, wonld enable a man on shore to 
raise a dam across that river, or if raised, to lower it to the bottom, in a 
few minutes. 

I have used this oontrivanoe for a fish sluice in a permanent dam, by 
which the water ran freelj through the sluices when necessary, and ai 
other times was retained at full height. 

The coaU on the descending navigation of the Lehigh, was sent to 
market in arks consisting of six boxes, 16 feet square and 20 inches deep, 
coupled by hinges, the whole carrying about 100 tons. 

Of course, it oftened happened in that hazardous navigation that the 
arks were wrecked. The lumps of hard coal were soon rolled down- 
stream by the current to some shoal below, where they were found in 
the form of completely rounded boulders. 

In making these improvements, eight hundred men were employed at 
once near Mauch Chunk, then in the wilderness, quite outside of the bounds 
of civilization. It was not easy to control these men, many of whom, 
doubtless, had never been remarkable for good order. The sheriff of the 
county was unable to make an arrest. But the fertile genius of Josiah 
White, and the strong good sense of Erskine Hazard, soon found a 
remedy. Under their inspiration the men organized themselves into a 
a republic, adopted a code of laws, which their backwoods poet put into 
rhyme, and these laws, which they themselves had made, were strictly en- 
forced and universally submitted to. Punishment was inflicted by a good 
stout hickory stick, as big as your finger, well laid on with a strong arm. 

The chief executive of this republic, called the lieutenant, was also 
the executioner. When all hands were called to witness punishment, 
they said or sang the part of the law which had been transgressed, and the 
lieutenant beat time on the offender's back. One of the gravest offenses 
was for a man to take more on his plate, or his shingle, than he could 
eat. Punishment of this soon stopped the grabbing, and the provision 
bills were very much reduced. At any official announcement, the ex- 
pression of loyalty to the supreme authority, was not as in England, 
** God save the King," or as in Pennsylvania, '' God save the Common- 
wealth," but " Hurrah for Mr. White and all the rest I " 

Engineers and employees may well take a hint from this piece of 
history. 

Josiah White, the Pennsylvania Archimedes, as he was sometimes 
called, invented, among many other things, the drop gate so valuable in 
canal locks of moderate rise. In 1827, he and Hazard built the Mauch 



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172 

Chunk Railroad, nine miles long, the first railroad (except a little tram 
road at Qoinoy granite qaarries) ever built in America. Mj hap was to 
ride on it within a few weeks after it was opened. 

In the early times of the coal business, the same coal passed in sue* 
cession through several hands, each of whom had an interest distinct 
from the rest. The owner of the land, the mine operator, the owner of 
the lateral road to the canal, the canal company, the boatman, the tide 
water vessel owner, and the coal merchant, must each make a profit, or 
he would stop, and that would stop all the rest, though, taken all to- 
gether, the profits made by some would greatly counterbalance the losses 
made by others. Hence, those parties who performed all the operations, 
succeeded best, for they always kept on and made something, while 
those who took the different steps of the business in succession were 
stopped, because some of them made nothing. Thus, the latter were 
driven to consolidate, though often against their earlier intentions. The 
owners of coal roads bought large tracts of coal land, not to monopolize, 
but to insure a constant stream of transportation, at times when private 
owners are accustomed to stop, because there is no profit in their 
branch. 

This generation wonders how the business of the world ever could be 
carried on, and especially, how railroads ever could be run, without the 
telegraph. And yet many of us remember when there was none. And 
after it was shown that information could be sent by an electric current 
through a wire, it was years before any one made use of it. 

About fifty years ago, Professor Henry made a series of brilliant dis- 
coveries in electro magnetism, one of which was, that by means of a 
current through a wire, a signal could be made and information given 
(by ringing a bell, for example), a long distance off. Years afterwards, 
Steinheil, Morse, Wheatstone and others, applied Henry's discovery to 
the actual conveyance of information ; Morse's apparatus, as it seems to 
us Americans, being by far the best. The wonder to us now is, why 
Henry himself did not apply his discovery, and why others did not 
sooner do so. The answer is found in a very important phase of human 
mind. The habit of mind into which the scientist is liable, perhaps 
likely, to fall, is to look at scientific result as his ultimate end. Such 
result arrived at, the same habit of mind is to use it only to attain fur- 
ther scientific result. Hence, men of science so rarely are benefited 
pecuniarily by their own researches. Hence, also, it frequently happens 
that engineers who have kept at their studies without practice till too 



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late in life, are so often less snocessfnl than those of far less science, and, 
perhaps, less inteUect, bat who have been early trained to apply to 
practical use what science they have. 

Iron ship building has had almost its entire growth within the last 
forty years. 

In the spring of 1845, I visited a small iron ship yard, then quite a 
new thing, at Birkenhead, on the south side of the Mersey. The .pro- 
prietor, in his green flannel roundabout, showed his modest establish- 
ment, and explained some of the processes. That proprietor became 
afterwards well known to the world as Sir John Laird, the great iron 
ship builder, and especially to this country as the builder of the Alabama. 
The operations of that enterprising craft came near involving us and our 
cousins across the water in a very serious conflict. This was averted by 
the moral courage and enlightened patriotism of Grant and Hamilton 
Fish on this side, and Gladstone and Clarendon on the other, who, not 
having the fear of demagogues before their eyes, agreed upon arbitration 
instead of war. All honor to the statesmen who took this great step in 
Christian civilization. 

They were just beginning to build the flrst dock wall on the red sand- 
stone bed rock of the Mersey ; now they have 159 acres of dock room 
enclosed. Then Birkenhead was a small village ; now it has more than 
100,000 inhabitants. 

America is not the only country that moves. 

Mr. Chanute, in his annual address, two years ago, spoke of the first 
propeller boat used in America. That propeller fell into my hands ; and 
I towed the first fleet of boats ever towed by a propeller tug on this side 
of the Atlantic, from Philadelphia to Bordentown, in October, 1839. 
Now, our harbors are full of them. The first propellers ever built in 
this country, and, as far as I know, the first iron hulls, were the Anthra- 
cite and the Black Diamond^ built on the plans of Captain Ericsson, and 
employed in carrying coal through the Delaware and Baiitan Canal. 
The first sea-going propeller built in this country was the frigate 
Princeton, built on Captain Ericsson's designs, under the direction of 
Captain Stockton. It was a full rigged sailing ship, the intention being 
to use steam only as auxiliary. 

It should not be forgotten that John Stevens, almost eighty years ago, 
built a small propeller boat, with two propellers, or ** circular sculls," 
as he called them, and ran it about the harbor of New York. It is won- 
derful how near his blades approach the angle which experience has 



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174 

shown to be best. He ased a small looomotive boiler, as it would now 
be called, such as was reinvented bj Booth, a quarter of a oentnry later, 
at LiverpooL 

The rapid progress of the oonntry, and the activity of the age, are 
more strikingly shown by the records of the Post Office Department, 
than by the increase of population — from three to fifty millions since the 
revolution — or than by any other statistics I know of. During several 
years of the time that Benjamin Franklin was Postmaster General, he 
personally kept the whole accounts of the department, and all in one 
small book, and settled with the postmasters and mail carriers. There 
were then about, perhaps, twenty or thirty dead letters a year, now 
there are four millions. It now takes eight clerks constantly employed 
to open them, and I remember that it takes fifty clerks to take charge of 
one class of them. Franklin kept one small book, which lasted three 
years, now there are 150 or 200 books, each half a dozen times as large, 
filled each year. Then the work was done by Franklin for $600 a year, 
now by 700 clerks, for, perhaps, a million a year. 

Within my memory, some of the sciences with which engineers have 
specially to do, have grown from infancy into at least adolescence. 

For example, geology was a collection of interesting but isolated 
facts, and unverified theories, now it is a science. It used to be con- 
sidered terribly heterodox, and a young man who cared to stand well with 
good people foxmd it safest to say nothing about it. To read 
geology was next to reading Tom Paine. A learned and excellent 
divine once confidently informed me that all the supposed plants and 
ftnimiila found in the rocks were merely stones that happened to come 
out in that shape. Now geology has an important connection with the 
instruction in theological seminaries. 

Business and population depend on geology. A geological map of 
England enables one to locate its occupations and the denser popula- 
tions. An outcrop of gneiss, extending southwest from New York, forms 
the limit of tide in the rivers, and fixes the location of Trenton, Phila- 
delphia, Wilmington, Baltimore, Georgetown, Biohmond and other cities 
to the southwest. 

When I studied chemistry at school, the components of compound 
bodies were given in percentages. For example, limestone was 48 per 
cent, oxygen, 12 per cent, carbon and 40 per cent, calcium. Of course, 
nobody could remember such proportions. Nor did it give the prox- 
imate elements of the compound. Theatomatic theory, as it was called » 



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175 

was known, bnt chemists were cantioas about aooepting it. Tbey had 
not yet learned to distinguish between the theorj of atoms, and the/ac^ of 
eqoiTalents. 

One of the most surprising feats of modem science is seen in the 
daily predictions we have of the morrow's weather. Time was, and many 
of us remember back to it, when predictions were made, and by intelligent 
people, too, from the phases of the moon, from weather breeders, from 
the weather on certain anniversaries, and the like. 

More than a century ago Franklin pointed out the fact that northeast 
storms begin at the southwest, two or three days earlier at New Orleans 
than at Philadelphia. Much information was afterwards accumulated, 
and scientific investigations were from time to time made by many able 
men. About forty years ago Prof. Espy of Philadelphia announced 
his theory, that rain is caused by the rarefaction and consequent 
upper movement of the mixed air and vapor into a colder region, where 
the vapor is condensed and falls into rain, and that this rarefaction 
produced by the heated surface of the earth, or by fire or otherwise, 
causes the denser air to fiow in from every side, so that the wind blows 
towards the rain. All this has been since verified. But this sanguine 
philosopher did not get the credit he really deserved, but drew upon 
himself the ridicule of the world, by claiming for his discovery more 
than it could accomplish, especially by proposing to raise the Mississippi 
by setting fire to the woods on the Alleghany mountains, when the 
hygrometer showed much moisture, and so getting the upward current 
required to make it rain, just as it commonly rains after any great fire, 
or the eruption of a volcano, or a battle. 

Espy visited Princeton to confer with Prof. Henry. I was present at 
the interview. Henry, while he thought Espy's main principle quite 
correct, got very much out of patience with him for several hasty con- 
clusions from statements which, to Henry's cautious, scientific mind, did 
not seem at all conclusive.* After he was gone, Henry chalked out the 
plan which he afterwards, with the co-operation of Guyot and other able 
men, so successfully carried into execution, of simultaneous observations 



* My Attention was drawn to this subject by the conference between Espy and Henry, and 
while traveling in Ireland, I asked my very bright, and, on the subjects within his range, in- 
teUigent car driver which way the storms there came from? Evidently he had never thought 
of that subject, but, adopting on the instant a meteorological creed, answered quick as 
thought : ** The storms, sir, come from whichever way the Lord Almighty chooses to send 
them." 



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all over the country, and a daily chart of highest and lowest pressures 
and other things about which my memory is less distinct. As everybody 
knows now, it is the traveling of these lines from west to east at an 
average of about 30 miles an hour, that enables the weather predictions 
to be made. 

Our rapid progess involves the frequent undoing of what has only re- 
ently been done in the most costly manner. We have seen expensive build- 
ings erected in the City of New York, and then in two or three years 
torn down to give way for something greater or dijSerent. The Alleghany 
Portage Railroad, of which my brother, Sylvester Welch, was chief 
engineer, W. Milnor Roberts being one of his assistants, was considered 
for some years one of the wonders of the world ; the improvements in 
the locomotive and the increased strength of the rails afterwards enabled 
engines to cross the Alleghany without the inclined planes used on that 
road, and that splendid work, on which so much thought had been ex- 
pended, was torn up. It is folly to build for the far future. 

This reminds me that in a paper written in 1829, read before this 
society two or three years ago, Mr. Moncure Robinson estimated that 
the tonnage over the Alleghany mountain at that point might in time 
reach 30 000 tons per annum. I suppose that the tonnage now over the 
mountain, on the Pennsylvania railroad, exceeds six millions. 

One of the bold and remarkable works of the day is the submarine 
sewer at Boston to carry the sewage under an arm of the harbor and 
across an island far to seaward. They have discovered, what unfortun- 
ately many others have not, that little is gained by emptying sewage 
into a harbor or into a small river, and so transferring the nuisance from 
one point to another, or distributing it all over. 

Sanitary engineers have been contending each for his own favorite 
system of sewering and draining cities. Mr. Hering, in his paper read 
at the Convention at Montreal, impressed upon us that no one system is 
absolutely good or bad, but either is good when adapted to the circum- 
stances, and bad when it is not. Municipal corporations often think 
that the remedy for un healthiness is, of course, sewerage, just as some 
doctors in old times gave their patients calomel without regard to 
what was the matter with them, or what kind of constitutions they 
had. 

One of the startling propositions of the day is to bring the waters of 
Lage George and the Upper Hudson by an open canal to supply the City 
of New York. When somebody asked Brindley what rivers were made 



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for, he said : ** To feed nayigable oanaLs." The answer now wonld be : 
** To supply great cities with water." 

Among the subjects to which the attention of the society is now 
especially turned are Standard Time and the Preservation of Timber. 
As we expect reports on these, I shall not further refer to them. 

One of the ipost remarkable of modern implements, one whose powers 
seem almost miraculous, is the diamond drill, which bores into the hardest 
quartz conglomerate and even into chilled iron. It seems to be capable 
of much wider application than it has yet had. 

The attachment of a car to a moving wire rope, in the way proposed 
by Col. Paine, without injury to the rope or risk to the oar, will probably 
revolutionize the mode of traction in very many cases. 

Within the last year or two the load on each wheel of a freight car has 
been increased from 5 000 lbs. to 8 000 lbs., an increase of 60 per cent. 
According to Dr. Dudley's observations on the Pennsylvania Railroad, an 
increase of 60 per cent, on a wheel made an increase in wear per million 
of tons of a little over 30 per cent. We may expect that this recent increase 
will increase the wear at least 30 per cent. ; that is, the rails on a heavy 
traffic road that would have lasted with the old machinery 10 years, will 
now last 7. 7 years. But with the heavier weight on a wheel, the residuary 
part of the rail after it is worn down to the limit of safety, must be much 
stronger than formerly required, in order to bear the heavier weight. Sup- 
pose the diminution of the consumable part of the rail on this account to 
be 20 per cent, (which would be only 4 or 5 per cent, increase on the 
whole rail) it reduces the duration to 6.16 years with the same traffic. 
But as the traffic has increased much more rapidly than was expected, it 
is now probable that the rails on our heavy traffic roads will not last half 
as long as they were expected to last three or four years ago. If a rail will 
last a dozen years where actually used, it would not pay to add more than 
about thirty per cent, to its cost to make it last two dozen years, but it 
would pay to add 45 per cent, to its cost to prevent its duration from 
coming down from a dozen to half a dozen years. Steel rails were made 
fifteen years ago with twice the endurance of those made now. Under the 
new circumstances, it is probable that it will before long be economy for 
roads with the heaviest traffic to pay the railmakersa price that will en- 
able them to make rails as durable as the best ever made. 

The concert of action among so many persons, and over so great dis- 
tances, essential to the safe, efficient and economical operation of our 



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railroads, and, therefore, to the safety and cheap aooommodation of the 
pnbllo, makes it necessary that all the operations of a ppreat system shonld 
bo in one interest and directed by one central authority. These might 
be governmental, bat in our country, at least, experience has shown that 
this is absolutely inadmissible. It is in the hands of great corporations, 
who have vast amounts of property and armies of men under their controL 
In some places every third man yon meet wears the button of a corpora- 
tion. Whether this concentration of power is in itself good or evil, it is 
inevitable ; and certainly a less evil than its alternative. The possession 
of this power carries with it grave responsibilities, especially in promot- 
ing the welfare of their employees. 

Many of the best and wisest corporations recognize the duty of re- 
garding their employees not merely as parts of a vast machine, but also 
as men. Saying nothing now of any higher considerations, they know 
that if they show a proper interest in their employees, their employees 
will feel more interest in them ; that if they provide a comfortable retreat 
for their train men when off duty they will not be driven to the liquor 
saloon for shelter ; that if they give facilities for intellectual and moral 
improvement to the men off duty they will be better, and especially more 
reliable employees ; and that if they give them the day of rest which Gk>d 
and human experience have alike declared to be necessary, they will be 
more efficient. 

Time was when corporations had very limited powers. Now they 
can do pretty much everything an individual can do, and a great deal 
besides. So officers could do little without specific authority from the 
directors. According to my recollection of the minute book of the com- 
pany, which in 1804 built the celebrated bridge across the Delaware at 
Trenton, at a cost of $180, 000 (a great sum at that time), the very first 
resolution of the board authorized the president to purchase two shovels 
and a crow-bar. 

The subject of uniform time for railroads is now claiming the special 
attention of this Society. It is of great importance, but it lias been so 
recently and so fully placed before the Society by Mr. Fleming and 
others that it is only necessary to call attention to their communications. 

The subject of tests for large members of metallic structures is now 
receiving our earnest attention. If I should speak of its necessity it 
would only be to repeat what is said in our memorial to Congress. I will 
only again call attention to one point ; that is, that the process of mana- 



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faotnre of a large piece of iron or steel may be so different from that of 
a small piece, and therefore the quality of the two be so different, though 
both may be made from the same stock, that the strength of the larger 
cannot be inferred, but only guessed at, from the known strength of the 
smaller. In the larger there is more likely to be permanent opposing 
strains that destroy a large percentage of its strength. A remarkable 
instance of opposing strains, caused by treatment in manufacture, waa 
pointed out some fime ago by Colonel Paine. He found that wire coiled 
before it was set could not be even straightened without straining the 
sides beyond the limits of elasticity, and that such wire had nothing near 
the strength of that coiled straight. As the strength of a large metallic 
member of a structure cannot be tested by any machine within the reach 
of individual means, and as to obtain the best results requires the com- 
bined skill of several classes of experts, the aid of Congress is invoked to 
provide a suitable machine, and to create a board of experts whose varied 
skill shall plan the best experiments. 

We are justly proud in this country of the system of checking baggage 
on our railroads. A traveler gets a check for his trunk at a hotel in 
Philadelphia, and gives himself no further trouble about it till he finds it 
at his destination, perhaps in Maine or Texas, or Oregon. It contrasts 
favorably with the system on the Continent of Europe, and especially 
with the want of system in England. But our handling of baggage in 
this country is shocking. A light English trunk will travel, all over 
Europe without injury. Here it is likely to be destroyed in a single trip. 
The greater weight of the stronger trunks required here costs the railroad 
companies quite an appreciable amount in the course of a year, and the 
damage to the trunk and its contents by the rough handling it gets some- 
times costs the passenger as much as his fare. And in the great majority 
of cases careful handling would not cost anything extra. 

What is, and is to be, the effect of all the activity and progress of the 
present day on human welfare ? 

Doubtless the preponderance of effect is good, but with many draw- 
backs. I will notice one : 

The rapid movement of the business of the world requires an immense 
amount of brain work to be done by those who direct it in each business 
day. This is made possible by the recently introduced facilities for 
rapid work. Formerly, when a man wrote his own letters, he thought 
sentences only as fast as he could write them. Now he dictates three or 



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four sentences to his stenographer in the time he wonld have been 
writing one, and so performs three or four times as much brain work per 
minute, as he would if he wrote himself. He does not go out of his 
office to confer with a man at some other office, but sits still and telephones 
him. When the railroad officer travels on his own road he does not chat 
with his friends in the public car, but goes in his office car, with his 
stenographer, clerks and table covered with papers. When a man goes 
home from his office he does not take the time to walk* but works on tiU 
the last moment, then goes on the Elevated Bailroad. The brain gets no 
rest, as it would have got in old times ; now constantly rushing forward, 
not standing in ita tracks, as formerly, while the man was writing down 
the thought of the previous instant ; now furiously at work, while for- 
merly resting while the man was going from place to place. This kept 
up for six or eight hours a day must soon break a man down, and has 
already broken down some of our ablest men. It does not mend the 
matter much that next summer he can spend a few weeks at the shore, or 
among the mountains. A man running up hill till he is out of breath is 
not enabled to keep on running another hour by the prospect of rest 
next week. A man that runs a locomotive twenty miles an hour may run 
all day, but if he runs sixty miles per hour, and so his brain and eye 
have three times as much to do per hour, he must soon stop to rest. 

Undoubtedly the progress of the age, which is so largely engineering 
progress, does on the whole greatly increase the welfare of mankind. By 
making the forces of nature do the hard work, the labors of the toiling 
millions are lightened many fold. The laboring man now works with 
brain and eye more than with muscle, and his business is now to apply 
some principle of science. This raises him intellectually. He now has 
time for improvement. Comfort and refinement, and even luxury, are 
brought within his reach. The forces of nature having become obedient 
to the will of man, they are made to produce for him not only plenty, 
but conveniences and luxuries formerly undreamt of. By the present 
facilities the races of men are 4)rought into contact with each other. 
Those races are being assimilated, and the prejudices and hatreds of the 
past are fading away. Supreme power among men is more than ever in 
the hands of the most enlightened, and they are sending civilization and 
Christianity into the regions most benighted. The light of Heaven is 
beginning to shine into the Harem and the Zenana. And the time seems 
to be hastening when there shall universally prevail ''peace on earth" 
and "good will towards men." 



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AMERICAN SOCIETY OF OIVIL ENGINEERS. 

INSTITUTED 1858. 



TR^NSj^CTIONS. 

Note.— Thl8 Society is not responsible, as a body, for the facts and opinions advanced 
In any of its publications. 



CCXXXVIII. 

(Vol. XL— June, 1882.) 



SUB-AQUEOUS UNDERPINNING. 

By A. G. Menocal, Member A. S. C. E. 



Read at the Annuaij Convention, May 17th, 1882. 



The quay wall at the Gosport Navy Yard was built between the years 
1835 and 1842. It was constructed of cut granite, and rested on a tim- 
ber platform, capping foundation piles, 18 feet below the coping, and 13 
feet 4 inches below the level of high water. For cross section of wall, 
see Fig. 1, Plate VL 

Soon after the completion of the work, the depth of water in front of 
the quay was found to be totally inadequate for the class of ships calling 
at that station, and the channel was improved by dredging. The excava- 
tion was gradually carried on, and it appears no apprehension was felt 
by those in charge, that the safety of the wall was involved in that ope- 
ration. The removal of the mud in close proximity to the foundation 



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182 

caused a gradual sliding of the material in front of and beneath the 
timber platform, and from around the piling, leaving the wood exposed 
to the attacks of the teredo, so abundant in those waters. The effects of 
this injudicious operation were shortly made manifest by a gradual set- 
tling of the masonry, not sufficient in amount, however, to occasion 
any alarm for several years. In fact, it was not until the year 1875 that 
a marked increase of the movement was observed. In a brief period the 
wall sunk several inches, and a decided outward movement was also ob- 
served. An examination of the foundations, with the assistance of 
divers, established the fact that both the platform and pile foundation 
had been partially destroyed by the teredo. The supporting power of the 
upper exposed ends of the front rows of piles was very greatly impaired, 
and the larger part of the weight of the structure rested on the two rear 
rows (see Fig. 1). The bond of the stone-work also contributed to the 
stability of the structure. With a view of arresting the settlement of the 
wharf, and in the hope of preventing its destruction, a row of eighteen 
inch square logs was about that time driven close together, and in imme- 
diate contact with the outer edge of the foundation (Fig. 1 A), but this 
expedient failed to meet the expectations, and the wall continued to set- 
tle at a rapid rate. 

A Board of three Civil Engineers of the Navy, under orders from the 
Navy Department, examined the work in 1880, and found that the 
greatest settlement was about 18 inches, and that the outer face of the 
wall had, in some places, moved 10 inches outwards. 

A new examination of the foundation by divers was found to be im- 
practicable, on account of the sheet piles in front, but the information 
afforded by the previous examination was thought sufficient to remove 
all doubts as to the causes of the damage. 

The sinking of the wall was evidently due to the partial destruction 
of the wood foundations, and the questions that naturally suggested 
themselves were : 

First. — Could any means be devised for permanently arresting the 
settlement ? 

Second. — Should the structure be demolished, and a new one erected 
in its place on an entirely new and deeper foundation ? 

The second alternative involved an expenditure far in excess of the 
amount available for these repairs, and additional appropriations for 
the same object could not be depended upon. 



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PLATE VI. 

TRANS.AM.SOC.Cn^. ENGRS. 

VOL. XI N9CCXXXIX 

MENOCAL ON 

SUBAQUEOUS UNDERPINNING. 





/^/0.4r. 



f^ .. 



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183 

The masonry was partially held in place by the bond of the oat-stone 
work, and any attempt at the removal of the material would destroy the 
integrity of the stmotore, break the bond, and quite likely result in the 
whole mass being precipitated to the bottom. In such a contingency 
the expense of the removal of the diebris would be a large sum, and 
could not be estimated with any close approximation. 

As the idea of demolishing and rebuilding the work had to be re- 
garded as a last resort, the importance of a thorough consideration of 
the first proposition was, therefore, too apparent to admit of discussion. 

A method of securing the desired object was submitted by the 
writer, who was a member of the Board, and it was adopted. The work 
was executed in accordance with the project submitted, which, briefly 
stated, was as follows : 

The portion of the wall most needing repairs was a stretch of 140 feet, 
where the movement had been greatest. This was marked off into sec- 
tions of about six feet each. Operations were commenced on the centre 
subdivision, where the sheet piling was first cut away ; then two founda- 
tion piles in the first, and the same number in the second row, were 
sawed off at the level of the bottom ; the remnants of the old platform 
were removed, and a recess was thus formed under the quay wall, some 
six feet wide by 6.5 feet high, and extending back 3 feet from the face 
of the masonry to the third row of piles. 

Upon the solid timber of the piling at the bottom 12" x 12" stringers 
were bolted, and on them 6-inch yellow pine planking was secured, then 
two stumps of piles in the same transverse (third longitudinal) rows 
were cut off, and the timber capping put on, this latter covering being 
usually a few inches higher than the one nearest the front (see 
Fig. 4). The two inner rows of piles (third and fourth longitudinally) 
were in some places found uninjured by the worms. Stout logs were 
in that case firmly bolted to the piles (see Fig. 3), and the platform 
carried on a level to the rear. The masonry overheckd, if showing signs 
of insecurity, was carefully shored and secured against falling. 
Upon the back or highest shelf of the stepped platform were then 
laid sacks of concrete, each containing no more than two cubic feet, 
the material arranged and placed so there should be very few, if any, 
voids between the different sacks. The concrete in contact with the 
stone masonry above, was thoroughly consolidated and rammed. The 
next lowest step was then loaded in like manner, with concrete in sacks. 



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184 

and bj this process a pier of hydraulic cement concrete, resting on a 
pile foundation, which was oat of the reach of the teredo, was formed 
under the centre of the wall ; then the subdivisions midway between the 
centres and the extremities of the long sections, were in like manner 
excavated and the wall underpinned ; next the subdivisions which were 
nearest the centres of the four intermediate spaces were cleared out and 
piers of concrete built, and so the work was continued until the com- 
pleted piers were but about six feet apart throughout the whole stretch, 
when work was carried on simultaneously on all remaining subdivisions 
until the gaps were closed. The cap pieces supporting the platform of 
the adjacent piers, were scarfed and bolted together so as to form as con- 
tinuous stringers as practicable under the circumstances. 

During the progress .of the work, the waU was left entirely undis- 
turbed, special care being taken to direct from it the adjacent land 
drainage. The filling behind the wall had become thoroughly consoli- 
dated, and exerted but little pressure on the masonry . 

The estimate submitted with the project, of the cost of underpinning 
140 lineal feet of the wall was as follows: 

282 Piles, cut, &tU «1128 

282 " capped, at $4 112S 

130 " cut in front row, at $2 260 

2 500 Feet Yellow Pine, for caps, at 40c 1 000 

20 000 " ** ** " planking, at 830 600 

2 240 Sq. Ft. Planking laid, at 50c 1 120 

700 Cub. Yds. Concrete, in bags, at ^15 10 500 

2 Sets Armor, for divers, at $1 200 2 400 

20 Diving Dresses, at 350 1 000 

Tools 500 

$19 636 
Add for contingencies 5 364 

Total $25 000 

The estimated cost per lineal foot was, therefore, about $178. The 
estimated cost of a new wall, excluding the expense of removing the 
debris and otherwise preparing the ground for the construction of the 
new foundation, was $447 per lineal foot. The work was under the im- 



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185 

mediate charge of Ciyil EDgineer P. C. Asserson, U. S. Nayj, who 
deserves much credit for its economic, rapid and judicious execution. 

Much difficulty was at first experienced in removing from under the 
wall the fragments of stone and timber, which had farmed with the clay 
and mud, a compact, stiff mass, very troublesome to move with the pick 
or shovel. A powerful jet of water from a hose attached to a steam pump, 
on the wharf, disintegrated these materials and they were readily removed 
to the desired depth. 

Operations were begun in the month of September, 1880, and 800 feet 
of wall had been completed in January, 1882, but much time was lost 
during the winters on account of the cold. 

The actual cost, including labor, material and tools, has been $125.10 
per lineal foot, or about $53 less per foot than the estimate. 

During the construction of the work a settling of only 7f inches took 
place, and since its completion no subsidence has occurred. 

The present depth of water at the foot of the wall is 21 feet six 
inches. 



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AMEEIOAN SOCIETY OF CIVIL ENGINEEES. 

INSTITUTED 1862. 



TRA-ISTS^OTIOlSrS. 

NoTB.— This Society b not roponsible, as a body, for the facts and opinions adranced In 
any of its publications. 



CCXXXIX. 

Vol. XI.— June, 1883 



THE MEAN VELOCITY OP STREAMS FLOWING 
IN NATURAL CHANNELS. 



By BoBEBT E. MoMath, Member A. S. C. E. 
Bead Febbuaby 15th, 1882. 



1. Ntunerons attempts have been made to discover a relation between 
the mean velocity of a stream and some observable element or elements; 
bnt the formulas proposed have all failed to satisfy when applied under 
the varying conditions met in practice. Still, a species of progress has 
been made, for the limitations of the problem have been one by one 
developed. 

2. It is now generaUy admitted that the solution cannot be a formula 
with general co- efficients. Local conditions control relations, and the 
pertinent question, of late, has been whether conditions can be grouped 



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187 

into olasses or categories, or must be treated in their individnal com- 
binations. Departing from the ordinary track of discossion, I propose 
to separate the natural stream from the artificial channel, because ab- 
sence of continuous bed slope, or gradient of bottom, is a radical dis- 
tinction in the conditions of flow, and to show that the definite law of 
discharge over a weir is usefully applicable at any transverse section 
above and within the influence of a weir, dam, or shoal. 

3. Of the two classes under which the formulas hitherto proposed 
may be arranged : the one which seeks a relation between mean and 
maximum velocity, after falling into disrepute, has again been brought 
forward by one of the latest writers as being the '* best means of rapid 
approximation to mean velocity." This unexpected conclusion is ex- 
plainable only by the fact that the Boorkee experiments were in a canal, 
and that sections of a uniform type, at localities where original bed 
slope had^ been preserved, were chosen for experimental sites. The 
general formtda 

Fmean = (7. F maximum, 
is equivalent to an assertion, that the mean ordinate of any figure bears 
a fixed ratio to the maximum ordinate, which is true of regular curves, 
i. e,, those whose quadrature maybe expressed in simple terms, but 
there can be no ratio common to all classes of curves. 

The transverse curve of velocity, resulting from plotting the means 
of all verticals, will have an outline which depends upon the transverse 
profile of the section. For strictly similar sections a ratio may be found 
which will answer reasonably well, but let the engineer clearly under- 
stand that its use is restricted to very narrow limits, requiring an exact 
repetition of all the essential conditions.* What the essential conditions 
are, and the improbability of their repetition, will appear incidentally in 
the course of this paper. 

For rivers, and natural streams in general, dissimilarity of section 
and variety of conditions forbid the use of formulas of this class. 

4. The second class may be represented by Chezy's formula : 

The particular form is of no consequence, for the criticism about to be 

* The ttrictneat ot the limitation U fully recognized bj Oapt. Onunlngham in his formal 
statement: "Central mean velocity measurement appears to be the best means of rapid 
approximation to mean (sectional) Telocity, but the redaction mnst at present be eir«cted by a 
coefficient to be found by prerious special experiment at each aite." 



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188 
made is not as to oo-effioient or exponent, but impeaches the terms em- 
ployed, hjdraolio mean depth, r = — : — - — and sine of slope, 

weif perimeter. 

The argument relied on is the following fact, furnished by the experi- 
ments of Mr. J. B. Francis at the Tremont weir and measuring flumes ;* 
and illustrated by accompanying Diagram 1, Plate VIL The discharge 
was determined by careful observation at the weir. Above the weir the 
water passed through a flume of rectangular section. At the side of the 
flame a gauge was set from which the depth of water in the flume at 
each observation was read . The experiments cited were made to deter- 
mine the formula of correction to be applied to vertical tube floats, and 
the facts were not only observed with care, but the suspicion of any- 
thing anomalous was carefully guarded against After a somewhat ex- 
tended series of observations, the flume being 26.745 feet wide, it was 
narrowed one-half or to 13.372 feet In both cases the sides and bottom 
of flume were smooth planking. The conditions above and below the 
flume were unchanged. 

In Diagram 1 the discharges by weir measurement are plotted as 
abscissas, to the corresponding depths in flume as ordinates. The full 
line curve presents the results of the wide flame observations, the 
broken line those of the narrow. It will be noticed that, for discharges 
greater than 250 cubic feet per second, the depths in flume were less 
after narrowing than before. It is certain that : 

1st. The width being one-half and the depth for a given discharge 
somewhat diminished the sectional area was reduced to less than one- 
half its former value ; therefore, the mean velocity must have more than 
doubled (F'> 2 F). 

2d. The surface elevation at the weir for a given discharge is a flxed 
level. A reduced depth in the flume means, therefore, a diminished 
slope from flume to weir, and local slope for any intermediate section 
must have been reduced (S <S), 

3d. The change in the section also effected a great reduction (30 per 
cent.) of hydraulic mean depth, therefore (r' < r). 
In the formula 

F=(7v/'r«r 



* See Table XXII. Lowell Hydraallc Experiments. 



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We have shown a second sfcate, V\ r', and ^S^, in which Fis greatly in- 
creased while both of the variable terms in the second member have 
diminished. If the co-efficient Chad been determined from the earlier 
observations it wonld ntterlj fail to satisfy the conditions of the changed 
section, though at the same site. If resort is made to a sliding scale of co- 
efficients, no material relief is afforded by D*Arcy and Bazin or Entter. 
Their formuUs wonld throw nearly the whole burden upon an increased 
slope somewhere. The facts show that no part of it was below the site. 

5. The experienced engineer is at no loss to know that the water was 
driven through the measuring flame by a head which was chiefly con- 
centrated as fall at the upper end of the flume. To that fall the term 
slope, as used by hydraulicians, 

is totally inapplicable. The sudden contraction caused an accumula- 
tion of head at the point of engorgement, under that head the velocity 
was accelerated, and the effect extended throughout the contracted chan- 
nel, indeed, to the brink of the weir.* The head producing velocity, in 
this case, would clearly be measured by the height of surface, a little 
up stream from the point of contraction, above a horizontal plane 
through the crest of the weir. The inappropriateness of the term slope, 
applied to the energetic hydrauUc factor, will be better apprehended if 
it be borne in mind that head is pressure, and cannot always be deter- 
mined by the level. The pressure of the octan tide forces the water in 
the Bay of Fundy to rise many feet above sea level, furnishing a clear 
example of the fact, by no means rare, that water does run up hill in 
oi>en channels. 

Sarface slope may afford a measure of head in a strictly uniform 
channel, but can have no place in dealing with natural streams. There- 
fore, in the problem this paper discusses, all old formulas are entirely 
set aside. 

6. Many engineers avoiding formulas have used diagrams of dis- 
charge, a curved line drawn through the points determined by plotting 
observed discharges as abscissas to gauge readings as ordinates, and by 
so doing have been able to interpolate discharges at dates and stages 
when direct measurements were not made. 

* There is reason to suspect that the slope from flume to weir crest became negatlTe for 
the larger discharges after the flame was narrowed. 



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190 

7. One need bat consider aJUeaiMLj what such diagrams are, to gain 
a starting point for farther studj far in advance of Gapt. Cnnningham's 
saggOBted retom to seeking a relation between mean and central velocity ; 
still farther in advance of snch as adhere to fanctions of slope and hydrau- 
lic mean depth. For the diagram of discharge, when capable of practical 
use (all are not), testifies to the fact that, under certain conditions, 
whose occurrence is not rare, there is but one independent variable, and 
that the readily observed element stage. 

^ 8. To reach discharge by Canningham*s method two elements must 
be observed for every desired result. Central velocity (which is, by hia 
own showing, unreliable, unless a mean of many observations) to obtain 
mean velocity, and stage to obtain areas. The diagram requires the 
latter only. The diagram is local in its application, but no more so than 
the co-efficient of reduction, ** to be found by previoas special experi- 
ment at each site. " Plainly, the preliminary observations will determine 
the diagram just as readily as they will the co-efficient. 

9. Following this line of thought, it will be profitable to determine 
under what combination of conditions the simple relation indicated by 
certain discharge diagrams is realized, with the view of extending their 
intelligent use.* To facilitate the gauging of streams is one object, to 
g^ard the profession against the improper use of right methods is an- 
other. In pursuing these purposes results will be developed that have 
an important bearing upon some branches of engineering work. 

10. The recurrence of fixed types of curve in discharge diagrams has 
already been alluded to, as conclusive evidence that but one independent 
variable enters into the problem of discharge. { This proposition is fun- 
damental. The actual recurrence of types is a fact reached only by ex- 
perience. 

11. From such experience the curves have been formulated for the 
particular case of discharge over a weir. Weirs differ greatly in their 
conditions, but the discharge over each kind of weir has its law in terms 
of one variable ; height above crest of weir ; for conditions become con- 
stants, and formulas are general only as conditions are similar. If such 

* OUssifloation aocording to local conditions it the basis of D'Arcy and Bazin's categoric* 
and Kntter's diagram. Their principles of classification are too narrow. Material and smooth- 
ness of wetted surface do not avail to explain the facts cited from the Lowell experiments, for 
these were not changed. 

t The reader will readily see that in rectangular and trapezoidal sections the yariation 
of area may be directly expressed' in terms of change of stage. 



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191 

law codrtB at the weir, it most of necessity exist at every section above the 
weir and within its influence ; for at all sections the discharge at any 
given time must be the same, and the local variations of stage mast 
follow those near the weir by a close and intimate relation. Hence there 
mnst be a definite curve of discharge at each section -vdien referred to 
local stage, under the condition that the sections undergo no change ex- 
cept a regular variation of area with stage. 

12. Discharge diagrams have often been suggestive of a parabolic law, 
and particular equations have in some instances been determined. But, 
since discharges approaching zero are seldom observed (low water dis- 
charge is far from zero), there has been an acknowledged difficulty in 
locating the axis of the parabola, which logically must intersect the axis 
of ordinates at the level of no discharge. In a channel of continuous bed 
slope the level of no discharge is at channel bottom, and, as volume di- 
minishes, flow ceases by extinguishment of depth when slope of stream 
surface is still considerable. Certainly a preferable condition for a dis- 
charge section would be a progressive diminution and simultaneous 
extinction of all the active elements of motion. 

13. Taking the case of a stream above a weir or dam, without ques- 
tion the horizontal plane through the crest of the weir is the level of 
no discharge throughout the pool, above such weir or dam (See Fig. 1, 
Diagram 10). In natural streams the bars or shoals are substituted for 
the supposed dam, and we may state as a general proposition. 

The plane of no. discharge is determined by the crest of the bar or 
dam (of greatest height if there be more than one), and is limited by the 
intersection of the tangent plane with the bottom at or near some supe- 
rior bar. . 

14. In a river this plane is the natural zero of hydraulic phenomena, 
and gauge readings might with propriety be referred to it, rather than to 
the imaginary standard of low water. 

15. Persons using discharge diagrams have often found, when carry- 
ing the investigation farther, that by factorizing the discharge (Q = V. 
A) and plotting mean velocities and gauge readings as co-ordinates a 
series of points was developed whose mean could best be expressed by a 
straight line ; that is, the relation between stage and mean velocity ap- 
peared to be a simple ratio. 

If the discharge section be rectangular, and many sites are ap- 
proximately so (considering only the part of section between high 



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192 

and low stage) » variatioQ of area is also represented bj a straight 
line.* 

The curve of discharge being the product of two functions, which 
may be considered linear, will be a parabola, if both the functions are 
straight lines, but in no other case. I enlarge upon this point (for there 
is danger of taking too much for granted in practical use of the method). 
If the gauge reading referred to zero of discharge be represented by A> 
and the section be a rectangle with bottom at zero, area {A) will be — 

in which, it will be remembered, width (w) is, bj hypothesis, constant 
Velocity is also supposed to be a straight line — 

F=Aft. 
The product is — 

whence A' = -r F, 

a common parabola, in which & is a constant to be determined. A dis* 
charge curve of this form would require three conditions : 1st. A. rectan* 
gular section. 2d. That the section be empty when flow ceases. 3d. 
That the relation between stage and mean velocity be a simple ratio. A 
little consideration will enable the reader to satisfy himself that the 
second and third conditions are inconsistent, and the combination im- 
possible. 

16. If the zero of discharge is a plane above the bottom at the dis- 
charge section, there will be for that section an invariable area below the 
level of no discharge, which may be represented by a ; its figure is im- 
material. If the section above that level be rectangular, the area vari- 
able with stage will be the product of width into gauge reading (A ^)> 
The total area is — 

Multiplying by V= /\b, the discharge is — 

Q=A V=^^bw + l,ab: (1) 

whence — 

A'+jA=,4,r: (2) 

but — is the mean depth of the invariable part of the section, and — 



* See Figs. 1 and 2, of Diagram 10. 



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193 

is the mean depth of the total area, representing these mean depths by 
d and D, equation (2) becomes — 

A* + d.A.=yF, (3) 

tmder the oonditions supposed, the formula for mean velocity would 

^^MA'+rf-A), (4) 

which contains one co-efficient to be determined, and one variable to be 
observed. 

17. The discharge curve for Section G, Connecticut river, shown by 
broken line of Diagram 6, is computed by an equation of the form (1) — 

C = 466 A' + 5556 A, 
An alternate branch at the lower levels is added to the diagram to illus- 
trate the risk of assuming lines to be straight from their origin, because 
a known part appears to be so. The true curve would lie between the 
alternates. At the higher levels the curve fits the observed discharges 
dosely enough to show its practical value, and to warrant the position 
that, under the conditions named, the formulas just obtained are practi- 
» cally true for a considerable range of stage below the highest. In failure 
at low levels, it no more than follows in the track of the best weir for- 
mulas. For, at the weir, the discbarge for small depths does not follow 
the law of relation to depth which is good at the higher levels, and I 
think the cause is the same. 

18. It will be noticed that the formulas contain two terms not 
hitherto used in hydraulics : 1st. Permanent area (a), or that of the sec- 
tion below the level of no discharge. 2d. Ruling depth, defined to be 
the depth of the plane of no discharge below the surface, at any given 
time and place ; its symbol is A- 

19. Thus fai* the argument has accepted the apparent straightness of 
lines of mean velocity as real. But the plane of no discharge being now 
definitely located at the level of the weir or shoal, he who may have 
diagrams of discharge, if applying the test, will probably find that his 
curves do not intersect the axis of abscissas at the origin of co-ordi- 
nates, but behind it ; and the line of mean velocities, if it appears 
straight, will, when produced, cut the axis of ordinates above the origin. 
Minus velocities and discharges are absurd ; therefore we must conclude 
that the straightness of the line of mean velocities is deceptive, and it is 
really a curve whose origin is at the level of no discharge. 



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194 

20. If mean velooities be a oarve, then the carve of discharge is of a 
higher degree than the second, and it is well to turn from its study to 
the simpler cnryes of its factors. In so doing, variable area will still be 
considered rectangular, and discussion will be confined to mean velocity. 

21. The fact that ruling depth, defined above, measures the phe- 
nomena has been sufficiently shown to justify its introduction as a sub- 
stitute for hydraulic mean depth. It is a representative of surface slope, 
if one be needed, for if ruling depths at any two sections be taken, their 
difference is the fall of surface. Logically, it is entitled to the position of, 
sole independent variable in a formula of mean velocity, for it measures 
head and the variations of area ; therefore of both s and r. 

22. If a stream be drained to its lowest limit, the surface in any pool 
will be a plane at the level of bar or weir crest. (In all strictness, the 
lowest point in the bar is the crest ; but in practical application to 
streams of considerable size a mean level of crest may be used.) Velocity, 
head, and discharge will all be extinct ; but at any given transverse sec- 
tion a certain area of motionless water may remain. This area has already 
been named permanent (for any section), and the symbol a assigned to it 
n, now, the surface be raised at any section by A» discharge begins, and 
mean velocity has a value which obviously must bear an inverse ratio to 
a. Increments of velocity, as /\ increases, will be so controlled by a 
if large, that the curve of velocity must be not only an orderly, but a 
very gentle curve. 

The cause of the apparent straightness of such curves is thus revealed, 
and we know that the one prime condition of a simple relation between 
Fand /\ at any site is a large value of a.* On the other hand, an excess- 
ive value of a would render increments of Ftoo small for accurate deter- 
mination of discharge. Therefore, a mean value for permanent area 
should be sought at a discharge section. 

23. The foregoing reasoning, and the evidence of observed velocity 
curves, which will shortly be considered, warrant the general proposition 

This function, when developed, may be so complicated as to be use- 
less ; it may be simple in its particular form as applied to a given series 
of observations, and yet be a resultant of many complications ; or it may, 
in its general form, be a simple expression containing constants appli- 



* TUB prime condition of Bimpllcity is directly contrary to Capt. Onnningtaam's condiulon 
that " Experimental sites should not be situated in marked hollows of the bed slope." 



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195 

cable to mdividnal cases only. It is sufficient to claim, at this stage of 
the discussion, that both elements are readily observed. 

24. A study of the accompanying diagrams is necessary to the further 
prosecution of the subject. 

25. Diagram 1 has already been described. It is a discharge curve 
for the section at the gauge in the two conditions of that section. 

Diagrams 2, 3 and 4 are representations of facts obtained directly, or 
legitimately derived, from Mr. Francis' Lowell Experiments. Diagram 
2 being columns 7 and 8 of his Table XIII. Diagram 3 is obtained by 
computation from data given in Table XX IT, and diagram 4 by a similar 
process from Table XVI. 

The curved lines B, of diagrams 2 and 4, are extensions of the 
observations by computing the discharges for heights not observed.* 
Observations, or the means of groups in most cases, are designated by 
dots. Lines curved or straight are added to interpret the observations. 

Diagrams 5 and 6 are obtained from Gen. Theo. G. Ellis* observations 
upon the Connecticut river, near Thompson ville. Observations taken at 
the several sections are designated by enclosed dots. Values obtained by 
transfer of discharges are represented by simple dots. The chief uncer- 
tainty about such transfers is the local stage. This source of error is 
small between F and O, but may be material at B and C. 

The remaining diagrams are not pertinent at present. 

26. Diagram 2 contains five straight lines passing through, or near to, 
the observations. The line A B\& tangent to the curve B and passes 
through the upper pair of dots only. The extension of curve B below 
the observations by computed discharges is mainly to locate the origin, 
and the origin so fixed may be taken as common to all velocity curves at 
the same locality, under like condition of weir height. 

The observations shown along the curve B were taken when the 
cross-section at the gauge station, 6 feet above the weir, was 13.96 feet 
wide and 5.048 feet deep below the level of the weir, less the area of the 
gauge boxes. The value of a was 70.02 square feet. Heights of surface 
at gauge above crest of weir (A) ^^ ordinates, and mean velocities past 
gauge are abscissas. 

The incomplete curve C results from a change of cross-section to 
9.992 feet wide, and depth, as before, 5.048 feet, a was 50.44 square feet. 

* These eztenaionB are for illustration only, and are not referred to in the subsequent 
argument 



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196 

The incomplete ourve D comes from a cross-section 13.96 feet wide 
and 2.014 deep below weir level, less the area of the gauge boxes, a being 
27.67 square feet 

The straight lines A C and A D fairly satisfy the observations of the 
two series last named. The line A D also satisfies the upper observations 
of the first series. The radiation of these lines from a common centre on 
the axis of abscissas will be noticed. 

The two points located on the line A' B' are observations taken with 
the cross section, as in the series O B, but the weir was divided into two 
equal bays by a partition. 

The points on line^' D are observations with section, as in series A 
D, but the weir was divided as in A' B', The convergence of these 
straight lines on axis of abscissas is again to be noted. 

The two points on short broken line C are observations under the 
same conditions as the series A C, except that the stream was prevented 
from spreading after passing the weir. 

27. For observations not specially designed for the purpose, these of 
Mr. Francis at Lowell Lower Locks, illustrate the subject under discus- 
sion wonderfully. The variety of conditions and combinations is very 
nearly that required, and the exactness of observation is beyond the 
limit ef expression by small scale diagrams. 

The convergence of lines in the diagrams may be suggestive, but ref- 
erence to figures will be instructive. 

Computing the co-efficients of the straight lines passing through the 
upper groups of the three series OB, 0(7, and 02), I obtain 

Straight line AB, X= 0.61345 (y— 0.2767) = 0.61345 y — 0.1697. 
'* AC, X= 0.72524 (y— 0.2338) = 0.72524 y — 0.1696. 
*• AD, X= 1.09013 (y-0.1592) = 1.09013 y — 0.1714. 
mean constant — 0.1702. 

The convergence of the straight lines upon a point in the axis of 
abscissas, at a distance in rear of origin equal to 0'.1702, measured in 
velocity, is thus put beyond question. 

Assuming the convergence to be at — 0.170, and computing the co- 
efficients that will best satisfy all the observations above a weir depth of 
1 foot, by method of least squares, I obtain empiric formulas: 
Series AB, V = 0.6144 A — 0.170, 
** AC, F=0.7253 A — 0.170, 
" AD, V= 1.0886 A — 0. 170, 



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197 

these co-effioients differ but little from those previously obtained hj 
taking the upper pair of observations in each series. 

If we were to entertain the thought that these formulas are good at 
lower levels, we would meet the absurdity that flow over the weir must 
oease when the surface only 6 feet upstream was in 

Series AB, 0/2767 above weir level, 

** AC, 0.2338 " 

" ^D, 0.1692 " " •* 

therefore a curved part must intervene between the lower observations 

of AC and A D and the origia, the same as shown by observation and 

computation for the series OB, 

28. In the observations represented by diagram 4, the conditions 
were materially changed. The model of a dam was substituted for the 
weir, the new profile having a level crest 3| feet wide, and a slope of 16| 
feet, extending to the cross section at which the mean velocity is to be 
determined. 

The discharge being actually measured in the lock chamber, mean 
velocity is easily found at any known section. The new section was 
9.992 feet wide, and 5.85 feet deep below crest of dam (by scale on plan), 
whence a was 58.45 square feet. 

From the experiments, a formula for the discharge over the dam was 
obtained by Mr. Francis, 

C = 3.01208/A»." 
and from computed discharges the curve of mean velocity is extended to 
A = 3'.4. 

The curve passes into a line practically straight at A = 2''^* '^^^ 
equation of the secant line ( A = 2.5 to A = 3'. 4) is 

r= 0.7258 (A — 0.461) = 0.7258 A — 0.3346. 
The co-efficient is almost the same as for the line ACoi diagram 2, and < 
we are reminded that the widths of section are the same. The section in 
itself considered is as if the bottom of section in the former position had 
lowered 0'.8. In this view diagram 4 would, if the original weir had been^ 
retained, have given another line to diagram 2 intermediate Uy AB andt 
AC If we were to transfer it to diagram 2, the actual line would be 
parallel to ^C7, but originating at — 0.3346.* 

* It win bo underitood that the mode of obtaining the tipper part of diagram 4 dlmlnlahes 
the valae of its evidence, oxo«pt at to general indications. No stress can be put upon 
paraUelism to JC. 



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198 

The shift of origin is by ready inference due to change in the form of 
weir (the level of crest was the same). Since th6 discharge for given 
heights above weir was lessened, the retraction of origin would appear to 
attend increased obstruction by the weir. 

The division of the weir into two bays, in another case, was also 
an increase of obstruction, and we see by diagram 2, that the origin 
moved forward. 

The series represented by the lines A'B' and A'ly are too short to be 
entirely conclusive, but it is hazarding little to say that both origin and 
inclination of the straight lines were changed by the division of the 
stream at the weir. Taking the figures for the two groups of observa- 
tions represented by A'B', and computing a line passing through them, 
I have 

F= 0.431 (A — 0.192) = 0.431 A — 0.0827, 
and for A'D' 

V= 0.768 ( A- 0.0988) = 0.768 ^ — 0.0759. 
mean constant 0.0793. 

The computed intersections with axis of abscissas, are very close 
together, and a trifling change would bring them to a common centre. 
We again have a practical convergence of secant lines for a given condi- 
tion of weir and varying section. 

Comparing the co-efficients of lines 

AB and A'B' we find^i^ = 0.7026 
AB 

AD *' A'D' " '* 4r? -.0.7045 
AV 

Wherefore the consequence of dividing the weir appears to have been 
a rotation of the lines AB and AD, without disturbing their relative in- 
clination, and a movement of the point of convergence along the axis of 
abscissas. In Diagram 4 we have movement along the axis of abscissas, 
and probable rotation in the opposite direction to that in Diagram 2. 
The effect of dividing the stream is evidently much more serious than 
that of change in form of weir below level of no discharge. 

29. Passing to Diagram 3, which represents experiments on a larger 
scale, and under conditions very unlike those of Diagrams 2 and 4, special 
note should be made of the fawst that the discharge section is much farther 
from the weir, and the channel between spread out to three times the 
width at the flume. Therefore regularity cannot be attributed to the 



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199 

direct draft of the weir. The relation of weir level to the bottom of the 
flume is not known, but is not far from 7'. 6. The velocity curves do not 
become straight lines, nor do the two secant lines approach a conver- 
gence at or near the axis. The weir condition was without variation, and, 
according to the precedent of the observations at the Locks, change in 
the section should not disturb the centre of the secants. This is a warn- 
ing against hasty assumptions. We should notice that in this series of 
experiments the velocities were considerable, and the gauge located in a 
still water box, where it measured a column of water sustained by the 
pressure of the stream upon the sides of the flume, and not the level of 
the stream. 

The diagrams have been made from the heights given in the tables, 
and for the practical purpose of this discussion the essential thing is 
shown by the observed heights, for the manifest simplicity and regularity 
of the velocity curve, with reference to stage, is seen not to depend upon 
theoretical niceties, but to belong to the observed values. 

In diagram 3 a pair of points, each representing a group of six 

observations, require a distinct line AB*\ These mark the effect of a 

' disturbance of the conditions of approach t»o the gauge section, by which 

numerous whirls were caused, and these are seen to have diminished the 

capacity of the channel. 

30. Summing up the positive teachings of the Lowell experiments, it 
is certain — 

Ist. There is a relation between mean velocity and ruling depth 
which is definite at any section under stable conditions. 

2d. The relation at a given section depends upon the constancy of — 

(a.) The section condition ; its area must vary only with the stage, 
not by scour, or fill or artificial change of area or form. 

(b,) The weir condition ; its height, form and freedom of discharge 
must not vary. 

(c.) Condition of approach ; no changes in direction or regularity of 
flow. 

31. To each of these three conditions the relation is sensitive to a 
degree that must satisfy the thoughtful Engineer of the hopelessness of 
obtaining a mean velocity formula with constants and co-efficients capable 
of extended use. 

The possible combinations of conditions are infinite, but we have 
reason to assert that each combination affords a definite relation at 



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all stages, hence constants and co-efficients locally determined are 
reliable. 

The third condition described mnst be, in efifect, the same as increase 
of area belcw weir level, to diminish velocity for a gfiven height of sur- 
face, and by so considering it the conditions (in kind) reduce to two, 
Section and Weir. 

32. The weirs of Diagrams 2 and 3 are arranged for complete contrac- 
tion. The dam section of diagram 4 gave a free overfalL The relation 
is not less definite in the one case than in the other. 

Diagrams 6 and 6 introduce an ordinary dam in a large river. No 
one will expect in these diagrams the precision of results seen in Mr. 
Francis* experimenta 

The height of dam is not stated, but its average was between 38 and 
39 feet on the gauge. Sections Q and F were at the ends of a short 
velocity base. G is some 3 800 feet nearer the dam, and ^ is an inter- 
mediate section.* O i<^and (7 have nearly the same area. B is the sec- 
tion of least area in the pool. Variable section is so nearly rectangular 
at each site that areas may be considered as straight lines. 

The observed mean velocities arrange themselves upon a straight line, 
with some notable exceptions. The numbers attached to the diagram at 
G' show the order of observation. 1, 2, 27, 28 and 29 stand to the right 
of the straight line and testify to velocities greater than the mean. It is 
a singular feature that both groups 1, 2 and 27, 28, 29 are for a faUing 
stage. The rising stage Nos. 24, 25, 26 are to left of line, and indicate 
velocities less than the mean for the stage, and very considerably less 
than prevailed at like stages during the subsequent decline, or just con- 
trary to the rule that velocities are accelerated by rising and retarded 
during the falling stage. According to received ideas this is an anomaly. 
By the view here brought forward it is probable that, owing to the ad- 
justment of supply and discharge, the river below the dam rose and fell 
relatively faster in this particular flood than in others ; that is, it is varia- 
tion of the weir condition by back water during rise, and freer fall during 
decline. Nos. 35, 36 also stand apart from the lines indicated by the 
other observations. A canal capable of passing nearly the entire low 
water volume is reported to be fed from the pool ; its opening must be 
at a level considerably below the dam, and it is to be expected that the 

* Fnr dptails of sections see Qeneral Ellis' Report, iu Bep. Chief of Engrs., 1878, Psrt 1, 
pages 361-353. 



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201 

control shotQd pass to the lower opening, when the volame there escaping 
becomes relatively great compared with that passing over the dam. With 
these explanations the apparent anomalies support the law. 

33. Uncertainty as to weir level prevents any attempt to trace relations 
or to determine the best line to satisfy the observations. That the line 
of Diagram Q is near enough for practical purposes is evidenced by the 
resulting computed curve of discharge represented by the broken line of 
Diagram 6. 

34 The diagram at section B has but three observed points, and they 
may be affected by weir variation ; but if they belong to the mean weir 
condition their teaching is important ; for from the direction of the con- 
necting line it would intersect the axis of abscissas in front of origin. 
Therefore the curve must be tangent to axis of abscissas, 'whereas all 
other curves, that have come under notice, have been tangent to axis of 
ordinates. At section B the river is not only shoal, but much wider than 
at G^, i^ or (7, and the dissimilarity of velocity curves arises from the 
relations of widths and areas.* 

35. Is has appeared in the course of this discussion — 

1st. Negatively, that hydraulic mean depth and sine of slope do not 
measure the phenomena of water flowing in natural channels. 

2d. Slope is a misnomer when applied to the distribution of fall and 
considered as the cause of motion. 

3d. Positively, motion is due to head or pressure. Near a weir it is 
customary to measure head by taking the elevation of surface above crest 
of weir at a considerable distance from the crest This distance being 
indefinite extends the relation of discharge to height above weir crest to 
all sections above the weir. 

4th. The level of no discharge is the natural reference plane for 
hydraulic phenomena. 

5th. Large sectional area below level of no discharge must, of neces- 
sity, limit the velocity to small and regular increments. 

6th. Weirs, dams, and natural bars or shoals define the level of no 



*If we c%rr7 the idea of diminished depth and are* to its limit, it will appear that the 
locality nnst become itself a weir. Another esse of tangency to axis of abscissas hss been 
deTelnped on the Mississippi below Memphis. This condition of the Telocity curve indicatea 
a section of nndne width, and sfTords a criterion to determine the width of a regulated river. 
A large area and slack current at low stsge is in the ioterest of nsTigation. Efficiency in dis- 
charge is a necessity in time of flood. Tangency to axis of ordinates meets both conditions. 
Tangenoy to axis of abscissas yiolates both. 



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202 

discharge at all sections above their sites, until the horizontal plane 
through their crests intersects the bottom of the channel. 

7th. Two new hydraulic terms are proposed — 

(1.) Permanent area, or that part of transverse section below the 
level of no discharge. 

(2.) Ruling depth, or the depth of the plane of no discharge below 
the surface at any time and place. 

The first is a constant at a given section, but may differ materially at 
neighboring sections. The second is variable, and in rivers measnrcB 
stage. For neighboring sections the differences will be the measure of 
surface slope. It also measures that part of 'area which varies with 
stage in>all sections having regular side slopes. 

8th. ,For a given site ruling depth is the only independent variable in 
the local mean velocity formula. The proof of this proposition rests 
upon the fact, that the best determined mean velocities, whether observed 
in natural or artificial channels, develop a smooth curve when plotted as 
abscissas to ruling depths as ordinates. 

9th. Most of these curves become virtually straight lines at a mod- 
erate value of ruling depth. 

10th. The curves, without impairing their simple regularity, are 
shown to vary with either of three conditions, namely : 

(1. ) yrhat of weir, dam or bar, as freedom of discharge is increased 
or impaired. 

» (2. ) That of the section, as its area is enlarged or diminlBhed, other 
than by change of ruling depth. 

(3.) yrhat of approach, such as change in the direction of current, 
or in th^ irregularities of motion, whirls and eddies. 

11th. The changes of curve caused by the 1st and 2d and 3d conditions 
are distinct and characteristic. Taking the direction of the upper parts 
of the velocity carves, after they become straight lines, and producing it 
backward to intersection with axis of abscissas, it is discovered that 
change of weir condition varies the point of intersection, and change of 
section condition varies the angle of intersection. 

These eleven propositions are put forth as proven, or capable of 
proof from the facts given in the diagrams. I add two theoretical propo- 
sitions, suggested by the preceding, bat shall not discuss them. 

1. The facts may be interpreted to signify that the velocity curves are 



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203 

hyperbolas ; weir oondiidon being transverse, and section condition the 
conjugate axis. 

2. The height of the cone from which the hyperbola is ctit is a func- 
tion of 2gh and area, h being the head available to produce motion at a 
given site. Each section furnishes its individual cone. See Fig. 3, 
Diagram 10. 

36. In practical application of these propositions to gauging streams, 
everything is made to depend upon local determination of constants. 
Therefore it will be assumed that something more is desired than a single 
gauging. 

Direct measurements of discharge by the best means and method 
available are essential. Let the local conditions be studied, that a few 
careful observations may give a local curve, which may be used with 
confidence so long as local conditions continue unchanged. 

1. A desirable site for observation to obtain continuous discharge 
will not be found at a bar or wide section, but in the pool, at a point 
where the area and width have a mean value. If the permanent area be 
too great, the variation of velocity for the lower stages will be imper- 
ceptible ; if it be too small, the law of the velocity curve will not appear, 
except by many observations covering the whole range of stage. 

2. Sites should afiford a distributed current, and in general should be 
taken in a straight reach as far from the preceding bend as possible. 

3. The influence of tributaries must be considered; go below, if nec- 
essary, but never immediately above one. Back-water from this or any 
other cause is change of weir condition. 

4. Choose a section with steep banks, and high enough to contain the 
stream at all stages. If this be impossible, be cautious of extending the 
curve observed below beyond the level of overflow ; for overflow is an 
important change of section condition. 

37. If these cautions are observed in choosing a site, a series of direct 
discharge measurements, including a considerable variation of stage, 
will furnish the direction of the curve of mean velocity after it has be- 
come practically a straight line. If the level of no discharge is also 
determined by observation of the controlling weir or bar, it becomes the 
axis of abscissas ; heights above level of no discharge are ordinates. 
The steps required to determine the intersections of the straight line 
with the axes need not be specified. 

The curve of mean velocity, if not a hyperbola, is very nearly one, and 



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204 

may be computed from the data bj considering the intersections with 
axes of abscissas and ordinates as defining the transverse axis {A), and 
the conjugate axis (B), respective! j. The mean velocity curve referred 
to vertex of transverse axis is— 

A'=f-I{»^+24r) (6). 

Theoretically, B and A are complex functions of a and 2gh. But the 
practical process described will, if the conditions stated are observed, 
determine their local value. If thought advisable, mean velocities may 
be combined with areas, and a table or diagram of discharge prepared. 

I add an additional caution. Choose times for preliminary discharge 
measurements when the stream is at a stand, if possible. If this is 
impracticable, obtain discharges at equal stages of rise and fall, and take 
a mean. 

38. To use the method described, it is essential that stage, A> should 
be observed at the discharge section, and that the seoti<m and regulating 
weir or bar be permanent. 

39. In many natural streams both section and bar are unstable. So 
far from this working a suspension of the relations under discussion, 
it increases their importance. The suggestion, that the condition of the 
wier or bar exercised a controlling influence over velocity in the pool, 
came from a study of data observed upon the Mississippi. In these data 
the law of ruling depth was disclosed by its variations. 

40. The purpose of the study was not so much to improve methods 
of gauging streams as to obtain light upon the important practical sub- 
ject of flood control. The retention of flood waters within definite 
bounds manifestly depends upon the constancy of the relation between 
stage and volume ; or upon the expectation that an assumed, or ascer- 
tained, maximum volume will always discharge through a given cross- 
section. 

41. Facts are on record showing that, at Columbus, Ey., in 1857 and 
1858, the discharge of the Mississippi exceeded 1 100 000 cubic feet per 
second four times. At the first rise, December, 1857, the discharge 
named occurred at a stage of 29'. 50 on the rise, and at 31'. 60 on the de- 
cline, difference 2^.10. The second rise, in March, 1858, the stages for 
like discharge were 32'. 50 and 34'. 70, difference 2' .20. The third rise, 
April, 1858, the stages were 33'. 50 and35'.90, difference 2'.40. At the 
fourth rise, June, 1858, the stages were 35'. 00 and 36'. 90, difference 1'.90. 



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205 

The mean of the differences, 2' 15, is all that can in any case be accounted 
for bj acceleration and retardation by stage. 

The sncoessive differences between stages of like discharge d'.OO -f- 
r.00 + l'.50 = 5'.50 on rise, and 3M0 + 1'.20 + 1'.00= 5'.30 on decline 
are evidence of the progressive impairment of the capacity for discharge. 
The mean of the sum of these differences, 5'. 4, suggests that overflow by 
the flood of 1858 was not due wholly to volume, but in a considerable 
part to an unknown cause, which diminished the capacity of the channel 
between December, 1857, and June, 1858. 

42. In a paper read at the 12th Annual Convention of this Society 
(No. CGVI, vol. 9, of Transactions), the writer discussed the variation 
of the section of rivers and showed, that a filling of wide sections at 
times of flood was to be expected in silt conveying streams, and 
conversely a removal of deposit during low stages*. If this fill be in the 
channel it is a building up of the shoal, and the subsequent scour is a 
lowering. 

43. In the present paper I have shown the importance of weir con- 
ditions by undispntable facts, and have, by natural inference, attributed 
like consequences to a change of dam, bar or shoal. There is a wide 
difference between a weir, discharging into open air, and a submerged 
dam or bar. I hoped that Captain Cunningham's observations might fur- 
nish facts that would definitely establish the inference : for the Ganges 
Canal is regulated by dams, which are varied at will and therefore afford 
many phases of weir condition. Unfortunately the ** state of control " 
is given by Cunningham only as a ratio of closed area to that of a full 
opening. I therefore must fall back upon inferior evidence. 

44. The diagrams of Humphreys and Abbot (Plates XTV, XV, XVI 
and XVn of their report), are discharge diagrams, but bear slight 
resemblance to the diagrams 1 and 6 accompanying this paper. If mean 
velocities were substituted for volumes, the resulting diagrams would 
present an intricacy like to the discharge. Tet out of the apparent 
confusion order will come, if the disturbing effect of three causes be 
allowed for. 

First. Velocities are accelerated by a rising and retarded during a 
falling stage. Rise and return to a stand at a given stage would produce 
a looped curve of velocity. The Columbus observations furnish four 

* A fuller discasBioD ot the same eabject will be found in Appendix K, and confirmatoij 
UctB in Appendix D, to Report of Mississippi Commission for 1881. 



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206 

distinct loopR : the breadth of any one loop is much less than the breadth 
occupied by all, and the influence of this cause may be to that of all 
causes, as breadth of any one loop is to the breadth of belt included be- 
tween extremes. If the figures be taken for each rise, as it passed a 
thirty foot stage, the breadth of Ist loop was 0.66, of 2d, 0'.52, of 3d, 
1'.08, of 4th, VA2 feet per second. Total breadth between extremes be- 
ing 3 feet per second. This cause, therefore cannot be credited with 
more than ^ of total effect, and probably this is much too great, for the 
progressive lessening of velocity between first and fourth rise must in 
part have occurred between the dates embraced in each loop, conse- 
quently the general cause has also widened the loops. 

Second. Change within the section by deposit or erosion. This may 
have been : 

Ist. An enlargement under the high velocities of the flood stage, 7i 
to 8i feet per second. 

2d. A deposit in the slack current of the low stage, li to 2 feet per 
second. 

3d. The irregular fleeting changes due to passage of sand waves.* 

The first two would be most active in producing irregularity at ex- 
tremes, and the results would be progressive during continuance of high 
and low velocity. Since, by remeasurement of section after the flood 
had passed, enlargement by several thousand square feet was observed, 
the broadening of the upper parts of the loops may have been due to 
this cause, but, since the observed enlargement was much greater at the 
lower of two sections, 200 feet apart, than at the upper, it is probable 
that the apparent change is due to a sand wave. Sand wave effects 
would compensate each other within a few days. 

Third. Variation of level of no discharge, chiefly by fill and scour at 
the regulating shoal situated at an unknown distance b -low the obser- 
vation station. 

Experience has taught navigators and engineers that the channel 
depth over a Mississippi bar is subject to change of several feet by fill 
during high and scour at low stages, its effect as weir variation should be 
correspondingly great. 

45. At Columbus the several loops furnish a straight line of velocity 
with a constant co-efficient, but variable origin. 



* The subject of land waves has ooly received attention during the last few years. See 
Appendix D, to Rep. Mississippi River Commission. 



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207 

The mean of all lines is 

V= 0.9212 + 0.1849 y, or practically 
F=0.185(y + 5'), 
the limits of extremes being (y + 11.1) and (y — 3'.0): y is the reading 
of the gauge, whose zero was 5'. 7 above low water of 1855. 

Variable origin of the straight line has, in the earlier part of this pa- 
per been identified as eflfect of change of weir condition. The present 
purpose is to see if change of origin measures variation of bar height in a 
river of unstable regime. The weight of the test depends wholly upon 
the probability of the results, that is their accordance in season, progress 
and amount, with what are now known to be general facts. 

Dividing each observed velocity by 0.185, and subtracting the corre- 
sponding gauge reading from the quotient, I obtain the positions at 
which the straight line would intersect the gauge at each date, and have 
plotted the results as lower line of Diagram 7; the upper line being stage 
of wftter. The change of bar height cannot be sudden, and I have drawn 
a broken line as a mean, to express the probable eflfect of weir condition, 
allowing the first two causes, named above, lio have produced the serra- 
tions shown by the full line. It is assumed that the vertical shift of the 
straight line alpng the gauge reflects, if it does not measure, the change 
in level of no discharge. 

46. By a similar process applied to the Vicksburg observations of 
1858, I obtain Diagram 8. The mean position of line is : 

V= 0.097 (y + 22.7). Limits y + 27'*9 

47. Similarily I obtain from the CarroUton observations of 1851, Dia- 
gr&m 9, mean position of line being : 

r=0.324(y-f4.0). Limitsy + g/^ 

48. The three diagrams concur in showing that the cause of velocity 
variation is associated with the greater or season oscillations of stage, 
having a minimum at low water, and a maximum following the culmi- 
nation of the flood at a considerable interval. The lesser maxima and 
minima follow the minor flood waves at Columbus and Vicksburg . 

49. These diagrams show the cause — varying as my former paper 
showed that bar height must vary. And the amount of variation of the 
lower lines of the three diagrams is in accord with the known changes of 
Mississippi bars. Identification in the absence of direct observation 
could scarcely be more complete. 



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208 

50. Oftrrying the teaohings of the weirs to the broader oase of river 
bars,* is now justified by the regularity and constancy of the relation 
between mean velocity and ruling depth when the latter is variable. The 
facts at hand furnish one more indirect, but, when apprehended, convinc- 
ing proof. 

The observations at Carrollton, which furnish data for Diagram 9, were 
123 in number, and made at <* Prime Base." At intermediate dates 8 
similar observations were made at "Prestoh Base,'* about a mile up- 
stream ; 3 at '*Race Course Base," 4 500 feet down stream ; and 4 at 
•* Locks Base," 9 000 feet below " Prime Base." Diagram 9 furnishes a 
measure of the variations of the level of no discharge at '* Prime Base," 
and it is certain, if tmth has been reached in the preceding discnssion, 
that these variations must be the same at all the sites. 

If for any observation the mean velocity be divided by the vertical 
distance between the line of stage and the broken lower line of Diagram 
9, for the corresponding date, the quotient will be the co-efficient of the 
straight line for the site, and for any site the co-efficient should have a 
constant value. (The influence of the other two causes of velocity varia- 
tion will cause the co-efficients so obtained to vary somewhat. ) Comparing 
the co-efficients determined for difiEerent sites they should approximate an 
inverse ratio to the areas at the several sites. The following table exhibits 
the tests : 

* Iq the original study the order wm reversed. Weirt oonllrmed oonolnsions reached tram 
discussioii of river data. 



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209 



SZTB AND 

Date. 


8ti««. 


From 
Diftgram, 


A 


V 


Ck>-effl- 
cient = 

V 


Batiob 


"Preston Bwe." 




A-SUffe. 






A 




Apr. 9.1851.... 


15.0 


3.10 


18.10 


4.84 


»-«^* °--'-^;^= 


•« 10, •• .... 


15.1 


8.00 


18.10 


4.70 


0.324 
0.2696, 0.264 ""^^^ 


•• 11, •• .... 


15.0 


8.00 


18.00 


4.64 


1 Pr^Btnn B. 
0.2578 1 Low water area ^^^^^ 3 


•• 1«, •• .... 


U.8 


2.90 


17.70 


4.76 


^^^^*'^ 1267 
0.2683, 160840" *""' 


•• 18, - .... 


14.7 


2.80 


17.50 


4.68 


0.2674 High water areas ^^?^' 


May 12. '• .... 


12.3 


2.30 


U.60 


3.87 


i ^^^'^ =1.226 
0.2651 179 210 


June 2, " .... 


10.9 


1.80 


12.70 


3.41 


0.2685 




Oct 20, •• .... 


1.7 


3.80 


6.60 


1.42 


0.2682 




HMn 










0.2640 


Co-ef., 1.227. Areas, 1.246 

















* Looks Base.' 



May 13. 1851... 
•• 20, •• ... 
June 4, " ... 
Oct 21, •• ... 
Mean 



12.1 


2.30 


14.40 


4.19 


0.2909 


10.6 


2.10 


12.70 


3.66 


0.2890 


11.1 


1.70 


12.80 


3.64 


0.2844 


1.7 


8.80 


6.60 


1.47 


0.2673 
0.2829 











^ , PrmeB. 0.324 , ,^, 

Co-cf. ^- ^ „- =„-oo.» =1.146 

Locks B. 0.283 



L. W. areas 



Locks B. 
Prime B. * 



172 058 
150 840 

203 170 
** 179 2T6 



» 1.141. H.W. areas 
» 1.134 
Co-ef., 1.145. Areas, 1.138 



'* Race Coarse.' 



May 16, 1861.... 

" 23, •• .... 

Jane 8, •• — 

Mean , 



11.6 
10.1 
11.0 



2.20 
2.00 
1.70 



13.70 
12.10 
12.70 



4.60 
3.94 
4.16 



0.3285 
0.3256 
0.3276 
0.3272 



„ w V. ^Till^ -0 994 
^•^•'^* 179210 -®*^ 



Co.ef. 0.991. Areas. 0.985 



The compated oo-effioients are fairly ooastant at each site, and the 
means approximate the inverse ratio of areas. The conclosion is legiti- 



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210 

mate that a common cause equally affected each of the four sites at any 
given date, but in a degree which varied with the season. 

51. Beturning to ''Prime Base/' the recorded data show that the 
mean depth (below a datum plane), of the upper section increased by 
6'. 76 feet between February and September, and the mean depth of the 
lower section, 200 feet distant, by 6'.82 feet. The indicated change of 
level of no discharge, comparing February and September, was about 
one foot rise. Hence the local change in section cannot be the cause of 
the variation under investigation, because such change could not have 
equally affected all the sites at a given time. 

52. The bar at the mouth of the river, in the light of the facts before 
us, must have acted as a dam submerged in back water, the level of no 
discharge being intermediate to crest of bar and Gulf level. The 
amount of variation shown in Diagram 9 and the times of maxima and 
minima agree closely with known variations of depth at the passes. 

The Mississippi, Connecticut and Mr. Francis' flumes present the 
same facts. In the case of the flumes, the weir or dam is the manifest 
cause of variation in level of no discharge. The Connecticut dam, and 
the Mississippi shoals are causes of like variation. 

^3. Aside from the general confirmation of a definite relation be- 
tween mean velocity and ruling depth, the facts last presented show 
that, having stage and mean velocity, we can measure the changes in 
what I have called the weir condition. By inversion of process, if stage 
and weir condition are given by observation, and the local co-efficient 
determined, mean velocity and discharge may be easily and closely 
estimated by the method already described. 

54. In a discussion which, though confined to old data, leads to the 
rejection of several notioas that have almost attained the standing of 
accepted traths, and which brings forward new terms to express a novel 
conception of hydraulic relations, I cannot expect to convince, except 
the reader studies, digests and repeats. Still less can I expect to have 
avoided obscurity in expression, or misinterpretation of facts. But I 
do hope, that discussion and study will lead to experiment in the direc- 
tion herein suggested, and experiment to better theory and practice. 



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-T-r+- 







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AMERICAN SOCIETY OF CIVIL ENGINEERS. 

INSTITUTED 185 2. 



lloTS.— This Society is not responsible, as a body, for the foots and opinions sdvanced in any 

of its publications. 



CCX L. 

(Vol. XI.— July, 188Q.; 



ON THE DETERMINATION OF THE FLOOD DIS- 
CHARGE OF RIVERS AND OF THE BACK- 
WATER CAUSED BY CONTRACTIONS. 



By WmiiiAM R. Hutton, Member A. 8. O. E. 
Bead Decesibeb 21st, 1881. 



With Disoubsion bt Theodore G. Ellis, Bobbbt E. MoMath, and 
William R. Hutton, Members A. S. O. E. 



The determination of the flood discharge of rivers from data long 
previonslj obtained, is not unfrequentlj required of the engineer. So 
long as the flow is confined within the river *s banks, the ascertainment 
of the discharge is easj, as the sections and slopes are generally tolerably 
well defined, and the usual laws of the movement of running water apply 
with reasonable approximation. But when the river passes its banks 
ftnd overflows the surrounding country, all such rules generally become 
nfleless. The obstructions caused by trees, bushes, houses, fences, crops, 



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212 

&c.f hinder the flow and canse eddies and cross carrents. The varying 
directions of the currents in different parts of the stream, the bodies of 
dead water, the return currents flowing in some casei up stream, all com- 
bine to render utterly unreliable any attempt to ascertain the discharge 
by computation from the cross-sections and surface slope. The vaiiety 
of opinions and methods upon this question among engineers is well 
shown by the evidence of the experts in the **Elmira crossing case," 
a suit which on this account has attracted the attention of engineers, 
and more especially of Kome members of the Society, at whose request 
the following statement is introduced, the writer having been employed 
as expert on the part of the Lackawanna Company : 

The New York, Lackawanna and Western Railroad sought to cross 
the New York, Lake Erie and Western, over grade, at Chemung flats, 
about 10 miles below the City of Elmira. The latter road at this place 
lies upon the southern side of the valley of the Chemung River, at a 
grade scarcely higher than the level of the ordinary annual floods of 
the river, and has often been damaged by the higher freshets recurring 
every few years. 

The selected route of the Lackawanna road, after passing over the 
Erie, crossed obliquely the valley of the Chemung by means of the fol- 
lowing constructions : 

1. A bridge of 3 sjmns of 150 feet ouch, if measured on the centre line 
of roadway, but only about GO feet if measured normal to the line of 
piers. The obliquity was so great that the lower end of an abut- 
ment or pier was 60 or 70 feet above the up stream end of the pier next 
to it on the south. This bridge crossed a high water channel of the river 
known as Parshaira Cove, and was known as the ** Cove " bridge. 

2. An embankment, 3 600 feet in length, and from 14 to 27 feet in 
height, across the flats on the south side of the river. 

3. The Chemung River bridge of -i spans, each 150 feet long, oblique 
to the lino of roadway 70*^, or 20° from a perpendicular. 

4. A temporary i)ile trestle, 750 feet in length. 

5. An embankment, 10 or 12 feet high, extending to the higher ground 
on the north side of the valley. 

The valley of the Chemung at and above the crossing is from half to 
three quarters of a mile in width, quite irregular in its direction and in 
form, and through it the river winds, sometimes on one side, and some- 
times on the other, in a bed from 400 to 600 feet in width. 



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213 

The area of the water shed of the stream above the site of the cross- 
ing, is aboat 2 800 square miles. 

After the official filing of the map and description of the Lackawanna 
route, the Erie Company, early in 1881, made ineffectual efforts to pro- 
cure a change of the line by means of a commission appointed for the 
purpose by the courts, which, however, confirmed the recorded location. 
Later in the year the Lackawanna road applied for a commission to ar- 
range the crossing and assess the amount of the damages to be paid 
therefor. 

This commission met in August, adjourned to the 20th September, 
and from 25th September to the 4th October, and finally completed its 
work and made its award, on the 3d of November last. 

The crossing was refused, and resisted by the Erie Company on the 
ground chiefly, that the construction of the Lackawanna railroad would 
increase the height of the flood waters above the crossing, and render the 
floods more than ever injurious to the Erie road, both by damage to its 
roadbed and by delaying the movement of its trains. 

The hydraulic experts were, therefore, called upon to testify as to the 
increased height to which the flood waters would be raised by the pro- 
posed Lackawanna works. 

This increased height, depended primarily upon the quantity of water 
carried by the liver in floods, and therefore that quantity became the 
principal subject of discussion, and gave rise to conflicting opinions, and 
widely differing results. 

The substance of the evidence, expert and other, bearing upon these 
points will stated as briefly as possible. 

It was shown by the evidence offered by the Erie that the flood of 
March, 1865, was the highest known, at which time the entire valley was 
submerged from side to side, the depth of water on the flats at the place 
in question being in i>laces 12 and 14 feet. Flood marks were shown, 
and their levels and distances given, which indicated a surface slope of 
0.000 607 and 0.000 72 for 2 800 and 2 400 feet, and average slopes for 
4 or 5 miles of 0.000 757. Cross sections of the flood were taken near 
these marks showing areas of about 24 000, 27 000, and 39 000, square 
feet. From these data differing results were obtained by the several 
experts summoned by the Erie road, varying with the formula used for 
computation, and the area of cross section adopted. A calculation by 
means of the Chezy formula (then called the Downing-D'Aubuisson 



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214 

formula), with the co-efficient of 100 as proposed by Downing, gave 
189 000 cubic feet per second. [The formula is , t? = 100 V i2 -S , 
the letters representing as usual, v the velocity, R the mean radius, and 
8 the slope.] For a second computation, by means of the same formula 
and co-efficient, but in which the deep and the shallow portions of the 
cross section were token separately, a method recommended by Prony, 
the result obtaiaed was about 204 000 cubic feet per second. 

A third, applying the original formula of D'AuLuisson [ t? = 94.74 
-\/^<S— O.llJ to "such data as were furnished" him — a formula 
" made for different purposes from this, however, and only a sort of in- 
" dication to aid the judgment in arriving at the result * ♦ * in 
" that way * * made the discharge 169 Hi cubic feet per second '* 
— which he "considered to be considerably above what the quantity 
"should be." * * * * * Then, looking at it in another way, 
he said that in the highest flood known on the Merrimac river, the 
greatest discharge was equal to a depth i of an inch in twenty- four hours 
applied to the entire water shed. Computing it at the same rate for 
the Chemung, with a water shed of 2 770 square miles, the quantity 
would be ** 55 8(50 cubic feet per second.'* 

" From the character of the water shed," he continued, *' I should 
" have no doubt it " (the discharge) " would be a good deal larger here 
" * * • and the true quantity would lie somewhere between these 
" two results, which are very wide apart * ♦ * I have no doubt but 
" that the first result is too high, and ♦ * * the last result too low, 
" and the truth is somewhere between them. I could do nothing else 
** * * but take an average of these two * * the mean result of 
" which is 112 652 cubic feet per second." * * 

On the part of the Lackawanna railroad, it was claimed, first : that a 
comparison of the foregoing quantities referred to the water shed of the 
Chemung Biver, with the maximum flood discharges of other rivers of 
known drainage area, indicated plainly that these quantities were by far 
too large. The Potomac was cited with an area of about 11 000 square 
miles, and a flood discharge of less than 200 003 cubic feet per second, 
and the Kanawna with a drainage of nearly 9 000 square miles, discharg- 
ing 118 000 cubic feet. 

It was thence deduced, first : that the valley at the site of the crossing 
was not a proper place to furnish the data for a computation of discharge 
—that the varying direction of the main river channel, which carried 



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215 

neaily half the entire flow, winding through, crossing and reorossing a 
valley whose general direction was nearly straight, its banks fringed with 
trees, the surface of the valley (or plain) obstructed by masses of woods 
and detached trees, and to some extent by houses, fences and the like — 
would so far hinder the flow of the water, and increase its surface slope, 
as to render any computation valueless, which was based upon measure- 
ments made at that place. 

It was shown by evidence that in the City of Elmira definite flood 
marks for the freshet of 18G5 could be obtained at a point where the 
channel was straight, regular and unobstructed, and suitable for meas- 
urement observations ; and it was assumed that the discharge at the site 
of the crossing would be to the discharge at Elmira in proportion to the 
drained areas at these points, respectively. 

It was also urged that the Ch^zy, or so-called Downing-D'Aubnisson 
formula, as well as that of D'Aubuisson, has been proved by more recent 
experiments to be incapable of correctly representing the flow of water 
in open channels, and that their results were not worthy of confidence — 
that the experiments of Darcy and Bazin, Humphreys and Abbott, those 
reported by Kutter, and others, showed that if the form of the Cb^zy 
formula was adopted, no one co-eflScient would apply to diflferent cases 
in which the conditions were not the same — conditions entirely neglected 
by the older hydraulicians. 

The Eutter formula was claimed to represent, with the best attainable 
accuracy, the results of all experiments on flowing water in open chan- 
nels ; and its application to the Elmira observations gave for the dis- 
charge 72 815 cubic feet per second. It had, however, been proved by 
the testimony in the case, that the river overflowed its banks above 
Elmira ; that the water gathered behind the embankment of th6 Erie 
Railroad which crosses the valley at that place, overflowed the embank- 
ment, cut it through, and ran down in another channel next the hills. It 
was, therefore, not included in the first computed discharge. Nor was 
there any way to measure it. As, however, when the embankment broke, 
the surface of the water in the pond above it was lowered, the outflow 
was evidently greater than the inflow, and the discharge through the break 
(of known dimensions) was in excess of the real quantity overflowing at 
the point referred to. Adding this quantity (6105 cubic feet) to the former, 
and increasing it in proportion to the greater drainage area at the site of 
the crossing, 91 547 cubic feet per second was claimed by the Lackawanna 



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216 

Cotnpanj to be the true, or rather the possible maximum discharge of the 
river in the flood of 1865. On rebuttal, however, it was proved by the 
Erie Company that a further quantity had escaped from the river in 
Elmira immediately above the place of mensurement, and was to be 
added to the 91 547 cubic feet ; and by cross-examination of the witness 
by the counsel for the Lackawanna, it was developed that this quantity 
flowed about one foot deep across a street 700 or 800 feet in length. 
There was no way in which any computation of the quantity could be 
brought before the Commission by the Lackawanna side, and none was 
made by the Erie, but the former company attempted to bring out the 

fact that if the street were treated as a weir, and the quantity flowing 

« 

across it were computed by the formula for the discharge of weirs, the 
result would be larger than if calculated in any other way— that in- 
creased by the proportion due to greater water-shed at. the crossing, 
it would be 3 500 cubic feet, and that the total flow of the river at the 
crossing, would be increased by it to about 95 000 cubic feet per second. 

It was, moreover, stated by witnesses produced by the Lackawanna 
Company that during the height of this flood, the State dam across the 
river at Corning, or rather the guard bank connecting the dam with the 
high ground, was overflowed and broken through, and thut the water in 
the pool fell in consequence 4 feet in about IJ to Ij hours, forming a 
wave which, as observed upon the piers of a bridge, was 4 to 6 feet high 
1 000 feet below the dam ; that a sudden rise of about 2i feet took place 
at a point some miles below, and of 2 feet at Elmirn, 18 miles from the 
dam. These statements were contradicted by witnesses in rebuttal, but 
are given as the bases of certain hypotheses which were introduced. 

The Erie witness upon tbL*» point testified that the break in the em- 
bankment was only 10 or 12 feet wide ; that the dam was drowned out, 
the water on both sides being about level with the top of the guard bank, 
that the water in the pool did not fall after the break, but was somewhat 
higher later in the day. 

The hypothetical cases submitted to the experts by the coonsel on 
each side were each based upon the testimony presented by themselves, 
respectively. 

The Lackawanna Company asserted, in general termp, that the efiect of 
the rupture of the Corning dam, as described by its witne.*>8e8, would 
be ft It many miles below, and guided by the evidence, and by the gen- 
eral theory of waves, and observations upon their formation and propo- 



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KEERIE.4 

si 

t,LACKA>AJ 
OWN OF CI 



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217 

gation ; supported also by the observed facts of an artificial wave created 
in aid of the navigation upon the river Yonne in France — a wave formed 
by the discharge of waters impounded in advance upon the lateral 
streams — the opinion was expressed that at the site of the crossing the 
additional height of flood due to the wtive caused by the failure of the 
Coming dam, would be from six to twelve inches. It was noted that 
the navigation wave referred to with a primitive height of 3 feet, reduced 
to about 2 feet at the mouth of the Yonne, its junction with the Seine, 
maintained itself with a diminishing height as far as Paris, 60 miles, at 
which point its height was about a foot. 

The experts on the part of the Erie were positive that the rupture as 
described by the witness called by their side of the case, would have no 
appreciable effect upon the height of the flood surface 28 miles below. 
Considering the case as described by the Lackawanna witnesses, it was 
thought the effect would be to increase the flood height by not more 
than two iuches. But in speaking of the hypothetical case put by tlie 
the counsel for the Lackawanna, as to the probable effect of a ruptnre 
which should discharge from the pool about 40 000 000 cubic feet in 100 
minutes, producing wave effects as before described, one of them esti- 
mated that the height of the wave at the crossing might be about a foot, 
adding however, that the case was an impossible one. 

The formula) for the ht^ght of backwater produced by a contraction, 
as used by the different experts, are nearly the same. They all give 
the head required to cause the necessary change of velocity in passing from 
the large section above the works to the contracted section, multiplied by 
a coefficient of contraction, which is given by the older authorities as from 
0.80 to 0.90, or from 0.70 to 0.95, depending upon the form of the star- 
lings of the piers, and in a general way, upon the size of the openings. 

The co-efficient of contraction was taken by some of the Erie experts 
at 0.80, which was considered by one of them not too low, although the 
pier heads were of good shape, because of the obstructions caused by 
the remains of coffer-dams about the piers, and perhaps for other 
causes. 

All the exp-^rts assumed that the bridge openings were equivalent to 
others of equal size made in an c^ in bank men t, crossing the valley about 
at riji^ht angles to its general course, omitting all consideration of the 
relative positions of the two bridge openings lengthwise of the stream. 

On the part of the Lackawanna, the question was treated in the same 



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218 

manDer, although it was claimed that the shape of the approach to the 
Cove bridge justified a higher co-efficient, and that at this point the 
actnal normal section should be used from the abutment to the bank of 
the Erie road, which would leave out of consideration the intermediate 
piers, although as one of these piers would be near enough below any 
section to affect the discharge through it, the obstruction due to one pier 
should be allowed for. It was also suggested that, as shown by Mr. 
Francis* experiments upon weirs, the contraction was dependent upon 
the number of piers, or of ends causing contraction, and upon the 
depth, and that the ordinary formula did not by any means correctly 
represent the conditions. The usual method, however, was used by the 
Lackawanna expert, with a co-efficient of 0.90, which was deemed to be 
authorized for the one bridge by the form of the approach, and by the 
great size of the openings of the other, exceeding that of any bridge 
from which co-efficients had been deduced. 

The results of the various computations gave as the height of back- 
water due to the constructions, 4.3 feet, 2.3 feet, 1.67 feet and 1.33 feet, 
and by the Lackawanna computations, 0.568 feet. 

The great difiference between these figures is in part accounted for by 
the fact that the height of backwater varies with the square of the 
velocity, and consequently with the square of the quantity of discharge, 
and inversely with the square of the co-efficient of contraction. A 
double discharge would therefore quadruple the height of backwater, 
and the difference caused by using a coefficient of contraction of 0.80, 
instead of 0.90, is as 64 to 81. The errors, therefore, of original compu- 
tations are greatly magnified by the application of them to this case. 

In addition, some of the computations for the Erie were made, count- 
ing the openings above the natural surface, while the Lackawanna sup- 
posed the earth under the openings to be cut down to the level of low 
water. 

Various opinions were expressed by the ex2)erts upon the length of 
openiug or water way in the fjackawanna embankment which would 
reduce the additional rise in floods to a merely nominal height so as to 
remove cause for objection on the part of the Erie ; but, it is believed, 
no calculations were made to determine the point, except one submitted 
by the Lackawanna, which showed that with an additional clear opening 
300 feet wide, normal to the current, the backwater would be reduced to 
3 inches in height 



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219 

The principal controversy in the case related to the nse of the Kutter 
formula for the flow of water in open channels. It was claimed by the 
Lackawanna company, and, in fact, substantially admitted toward the 
close of the case, that while this formula might give very absurd results 
in certain hypothetical cases not included in the experiments upon 
which it was framed, it did correctly represent the result of those experi- . 
ments and observations ; that these observations covered a wide range of 
Streams and rivers, large and small, with steep slopes and flat ones, and 
that by a study of these examples, an engineer could select the case most 
nearly approaching his own, and find there a reasonably safe rule to 
guide his computations. On the other hand, it was urged by some that 
the exercise of judgment on the part of the engineer could not be dis- 
pensed with— that he must make such reductions from the results given 
by the Downing-D'Aubuisson formula as his judgment and experience 
alone might suggest, being without other recourse. 

Extract from award of commission : 

***** They deem it necessary to state their views in regard to 
the floods of the river and their effects^ and the course of reasoning 
which has led them to their conclusions. 

*' The testimony shows the flood and flood marks ; the experts diflered 
largely as to the effects to be produced on them by the works of the 
Lackawanna Company, but agree as to the rule by which it is to be com- 
puted. The differences in the results arise from three main causes, 
namely, the difference in the estimated volume of water, the assumed 
slope of the surface of the flood, and the co-eflicient used to represent the 
sinuosities, roughness, slope, form and volume of the flood. 

•*The results arrived at by Mr. Francis, who was called by the Erie, 
and Mr. Hutton, called by the Lackawanna, come nearest to agreement, 
and if they had used the same volume of flooil, their agreement in re- 
gard to the computed rise would have been much closer. 

»«*♦♦♦*»« 

** Under these circumstances, the commissioners have caused calcu- 
lations to be made by which they have formed the opinion that the vol- 
ume of the flood of 1865 was about 100 000 cubic feet per second. 

"And after making all allowance for the excess of that flood over 
all other known floods, and the effect of the break in the Coming dam dur- 
ing that flood, the oommisioners have determined the amount of bridge- 



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228 



Discussion by Theodobe G. Ellis, Member A. S. C. E. 

In the controversy between the Erie and Lackawanna Bailroads to 
which Mr. Hutton refers, one of the points in question was regarding a 
proper formula to be used to obtain the discharge of the Chemung River, 
with the data given. These were, as stated by Mr. Hutton, the average 
slopes for four or five miles, the slopes for 2 400 and 2 800 feet, and cross- 
sections at three diflferent places. With such data but the roughest ap- 
proximation to the volume of discharge can be obtained. The refine- 
ment of using a somewhat complicated formula like Ghmguillet and 
Kutter's in such a case is worse than useless. It gives an apparent accur- 
acy where there is none in reality. In order to use any slope formula 
to obtain the discharge of a stream, it is necessary to know the slope 
with the greatest exactness, and to have the exact mean section of the bed 
through the whole distance. One section, or even several sections, will 
give no good approximation even, by which the discharge can be com- 
puted. It was in this view that some of the experts in the case referred 
to gave the opinion that the Ch^zy formula with a co-efficient of from 80 
to 90 was a safer one to use, and just as likely to give a correct result as 
the Kutter formula. The question was not which is the best general for- 
mula, but what was the best suited to the peculiar circumstances of this 
case. 

A very common error of the inexperienced is to imagine that by a 
multiplicity of figures and computations they can get exactness out of 
inexact data. In the present case, by any formula known, the result 
might be from one-half to three or four times the truth. It would de- 
pend entirely upon how near the slope and section were to the mean 
slope and section of the stream. 

All formulas depending upon the slope and mean radius, whether they 
include the character of the bed or not, are indeterminate and mislead- 
ing. It is not yet known even what roots of these quantities should 
enter into the formula. They vary in different authorities from the 
square root to the sixth root of these quantities, and it is not yet known 
whether the surface should be included in the perimeter or not, and 
more than this, there is no knowledge whatever as to the laws which 
govern the position of the thread of greatest velocity, and it is known 
that its relation to the mean velocity is not constant. 

Kutter 's formula is a good one, being an empirical formula derived 



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PLATE XVIII 
TRANS. AM. SOC. CIV. ENGR'S. 
VOL XI. No. CCXL. 
HUTTON 
ON FLOOD DISCHARGES. 




Z^f^ 



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229 

from exi>eriment, but only for the streams for which it was calculated. 
It is bj no means certain to be correct for any other stream, though it is 
probably the best for canals and masonry channels that has yet been ad- 
vanced. Its classification of the beds of channels is simply misleading. 
This was shown in the computation for the Mississippi to which Mr. 
Hutton has referred. He thinks the formula should not be used in that 
way. Why not ? It gives a certain co-efficient to be used with certain 
roughness of surface in the bed. Now, if those co-efficients cannot be de- 
pended upon for all channels, what is the use of giving them. If the 
engineer has to vary this quantity for the size of the stream, why not 
exercise his judgment in the first place in fixing the value of the 
co-efficient in the Gh^zy formula from ' which Kutter*s is derived. It 
would be much more simple and fully as accurate. The classification by 
absolute roughness in the Kutter formula is its chief point of weakness ; 
if the roughness were made relative to the size of the stream, its deduc- 
tions would probably be better. 

In deriving their formula from the observations upon rivers, especially 
large rivers, a certain co-efficient of roughness was taken for their beds, 
and if this co-efficient is agaiii assumed in a computation for their dis- 
charge, it would be very strange if the desired result should not be ob- 
tained. But if it is necessary to always use this co-efficient for rivers, no 
matter what may be their bed or its character, there seems to be no gain 
over the Gh^zy formula with a constant co-efficient. Mr. Hutton says : 
"The sweeping condemnation of all mean velocity formula, with the ex- 
ception of that of Herr Kutter, is * * * fully borne out 
by experiment" — the experiments of Captain A. Cunningham on the 
Ganges Canal. 

Let it be borne in mind that these experiments were very accurately 
made upon a large canal, being a regular channel, the exact character of 
whose bed was known, being tho most favorable conditions possible for 
any such formula. 

The maximum discrepancies between the exact gauging and the re- 
sults given by the Kutter formula, are as follows : 

In the right Solani aqueduct, from — 21.7 to -f 19.5 per cent. 

In the embankment, main site, from — 14.0 to -f 42.3 per cent. 

Thus, in a canal under the most favorable conditions, and with mea- 
surements taken with the greatest accuracy, being exact means and exact 
slopes, the Kutter formula is found to vary from —21.7 to + 42.3 



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230 

per cent, of the whole discharge. A total yariation 'of 64 per cent 
of the whole flow. So it seems that even under these favorable circum- 
stances and in selected experiments, which prove the formula, it is 
barely possible the formula may be subject to a slight error. 

Captain Cunningham says that the error of the Eutter formula will 
seldom exceed 7i per cent, in large canals. 

But for this accuracy it is essential that : 

" The slope measurement should be done on both banks, always in calm 
air, and only when the canal is in train, and should be repeated several 
times." 

*' And further, for this accuracy it is essential that the ' rugosity co- 
efficient ' — / — be properly known for the site in the first instance. 
This of course can be only properly determined by experiment, t. «., by 
determining a few experimental values of C from which to determine /, 
either by direct calculation, or by comparison with published tables. If 
the value of / be merely selected a priori by comparing the known state 
of the channel with the published classification, so close an approxima- 
tion will be mere chance.'* 

That is, in large canals, if you can compute the co-efficient from 
experiment, Kutter's formula will give the discharge within 7i per cent 
Cunningham also says : That the difficulties in this matter seem to the 
author "to make further research for an improved form of co-efficient 
almost hopeless from the experimental side, i. «., until some help as to 
the proper functional form can be obtained from theory." 

He also says : 

" There can be little doubt that the mean velocity is in some way 
conditioned by the surface slope, but the law of connection is at present 
wholly unknown, the [present formulse being purely empirical, resting 
on no rational basis, and, therefore, only of limited and uncertain appli- 
cabiUty." 

It must be remembered that this is stated for regular canals where 
such formxda are recognized as being most correct 

For rivers, it is the writer's experience that there is no positive rela- 
tion between the volume of discharge and the surface slope. On the 
Connecticut River, where an exact survey of the bed of the river was 
made by sections every 400 feet, and in many cases only 100 feet apart, 
and the slopes were as carefully leveled as possible, a selection of the 
best experiments varied with the principal modem formulas from about 



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231 

one-half to two and one-half times the measured discharge. In the 
opinion of the writer, the slope is so uncertain an element, that the co- 
efficient used in nataral streams is within certain limits immaterial. The 
very best slope formulas can only be depended upon as an approxima- 
tion to the real discharge. They should only be used where no velocity 
observations are attainable, one single velocity measurement in the mid- 
dle of the channel being better than any or all of the slope formulas. It 
is only in such cases as the Chemung where the slope can only be taken 
from old marks that such a method should be resorted to, and then the 
channel in which the water flowed should be carefully measured and its 
mean section taken for the distance where the slope is known. 

The complexities and refinements of such formulas as Kutter*s, are only 
suited to regular channels like canals and sewers, where the slope is 
uniform and the resistances determinate. 

For natural streams of small size also, where the slope is great, and 
the nature of the bed conforms to one of Eutter's classifications, the 
Kutter formula may be valuable, but for problems where the "guess and 
allow " and '* average judgment *' rules come into so great an extent as in 
the Erie matter, to try to get down to entire accuracy by any formula is 
absurd. 

Mr. Hutton remarks that '* the point was made in this case, and 
many times repeated, that it was immaterial what formula was used to 
compute the flow of water, because in every case corrections must be 
applied which required the exercise of judgment on the part of the en- 
gineer. " Now, the writer was one of the experts employed by the Erie 
Bailroad, and he certainly never made any such point or heard of its 
being advanced. The point he made was that with the entirely insuffi- 
cient data given, there was no sidvantage in accuracy in using the Eutter 
formula over the Oh^zy formula with a proper co-efficient. The idea 
that it was immaterial what formula was used is simply absurd. Very 
few of the older formulas are even approximate under the best of condi- 
tions, and Mr. Hutton's remarks about them are entirely correct. The 
Ch^zy formula, however, still holds its own against most of its competi- 
tors, and for all practical purposes is as accurate for natural streams as 
the more complicated one of Eutter derived from it. "With exact data 
and careful measurements of slope and bed, the Eutter formula is ad- 
mitted to be the most likely to give close results, but when uncertainties 
are introduced it is best to adhere to the more simple form. The uni- 



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232 

formity of co-effioients given to the Ch^zy formnUt by different anthori- 
ties is a high recommendation of its general use. Eytelwein givea 
93.4, Young 84.3, D'Abuisson 95.6, Downings k Taylor 100, Leslie 
68 and 100, Stevenson 69 and 96, Beardmore 94.2, and Neville 92.3, 
and 93.3. 

The mean of these is about 90, which is perhaps the best general co- 
efficient. For the Ohemnng, with its overflowed banks and obstacles in 
the bed, 80 was recommended, and it would be almost a miracle if the 
result of this or any other formula with the data given would give accu- 
rate results. 

Mr. Francis' estimate of the discharge, being a mean between the 
two quantities of 55 860 C. F. per sec, and 169444 C. F. per sec., is 
112652. These amounts are wider apart than any of the coefficients pf 
the Gh^zy formula, and it is not exactly seen how they prove the accn- 
curacy of the Eutter formula by having their mean agree with its re- 
sults. 

Discussion by Robert E. MoMath, Membbb A. S. C. E. 

Sin(ie the Boorkee experiments of Gapt. Gunningham make no ex- 
ception in favor of Herr Kutter*s formula when making a sweeping 
condemnation of all calculated mean velocity formula, there is manifest 
need of a practical method of meeting the question presented in Mr. 
Button's paper. 

In important cases, like the one stated, I propose the following as 
practicable, and giving a close approximation to results obtained by 
direct measurement. 

The problem is to determine the discharge of a river at a given date 
of which the sole record is the stage. 

Where, as seems to have been the case with the Ghemnng, a reach 
can be found in which the river is confined to a definite bed the matter 
is simple, but requires time and labor. Assuming that a section can be 
found affording a consideral>le area at the lowest stage, it is necessary to 
determine by observation the mean velocity of flow at stages differing as 
much as possible. A short series at a low and another at a high stage 
will suffice, but others at intermediate stages are desirable to establish 
the result. 

These mean velocities will, under the condition of a large low stage 
area, when plotted as abscissas to stage of water as ordinates, lie on or 



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233 

very near a straight line. Extending this straight line from the highest 
stage of measured discharge to the height of the recorded or traditional 
flood, the abscissa of the line at that height is the mean velocity which 
would resnlt if the stream should now rise to the recorded leveL Having 
the area the discharge is known. Such discharge may be attributed to 
the former date with liability to error, only as the local area has changed 
and as the crest of the bar or dam next below the observation site has 
been raised or lowered. In rivers of permanent character the changes 
by natural causes will be small ; obviously the change of local area would 
equally affect any computation. Variation of the bar or weir height is a 
change in the level of no discharge, or the origin of velocity. 

Should no locality be found where the stream was within banks at 
flood, another important condition must be observed. The stream at 
the selected site must conform to the general direction of the valley; that 
is, the direction of flow within and without the banks must be sensibly 
the same. The method proposed will give the mean velocity within the 
limits of the principal banks. The volume flowing over the bottoms 
must be estimated as best it may. I would only say that all computa- 
tions tend to exaggeration of the overflow water. 

In a series of observed discharges of the Mississippi, below Memphis, 
16 out of 66 were used to determine the line of mean velocity according 
to the proposed method. By the resulting equation F'= 0.0725 (gauge 
reading + 37 '.2), a series of F' was computed which when compared 
with the Fby direct measurement gave : sum of 66 residuals [F' — F]= 
5'.481, whence mean error = 0'. 083 : minus errors 31, sum 2'.438, mean 
0'.078. Plus errors 35, sum 3'. 053, mean 0'.087. The maximum error 
was 0^.366 in a velocity of 4'. 873, or 71 per cent The per cent of error 
between computed and observed velocities was in 
22 cases less than 1 per cent. 



38 


ec 


2 




47 


it 


3 




57 


t( 


4 




63 


C( 


5 




65 


(< 


6 




66 


<( 


8 




The mean error 


being 2i 




The range of stage covered by 


the observations was from 6'.0 to 27'. 0. 


The greatest observed discharge was 825 000 cubic feet per second. Ex- 



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234 

tending the computed F' to a 29 foot stage, the maximum discharge for 
the year 1879 is found to have been 911 400 cubic feet between banks. 
During the recent high water, March 6-9, 1882, the data indicate a dis- 
charge between banks of 1 251 200 cubic feet per sec., stage 37'. 9. 

Assuming that the volume, including overflow water, at top of flood 
of 1882, was 1 700 000 (a fair approximation), the height to which the 
flood would have risen if confined within width of 4 700 feet would have 
been 37'.9 + 9'.9 = 47'.8 f or ^ r = 1 251 200 = determined Q at stage 
37.9, and A'v'= 1 700 000 = Assumed Q' at stage 37.9 + V; 
^ = 230000n'; v =5.44; ii7 =4 700'; ^ = 37'.9+ 37'.2 =75'.l ; then 
(A + w h') (h + V) 0.0725 = 1 700 000 ; whence h'= 9' .86. 

I have now for illustration applied the method to two problems, 
neither of which could have been satisfactorily solved by the methods 
heretofore in use. I have also shown the degree of approximation reached 
by the method in an unstable river. The section enlarged by scour, 
10 400 square feet, and then returned to its first condition during the ob- 
servations. This change affects the velocity somewhat but the residuals 
were mostly the effect of variation in the level of no discharge, by scour 
and fill at the bar next below the observation site. In a stable stream 
the approximation ought to be closer. The observations which were 
made by H. B. Herr, 0. E., assistant under Major W. H. H. Benyaurd 
were exceedingly well made, and the site happily chosen. 

Discussion by WiLUAif B. Hutton, Member A. S. C. E. 

As Major Cunningham concludes that *'Kutter's co -efficient c is of 
pretty general applicability," and that with accurate data it will give 
reasonably correct results, he, at least, does exclude the Kutter formula 
from any *' sweeping condemnation" of calculated mean velocity for- 
mulas. He would, indeed, prefer a formula depending upon velocity 
measurements rather than on measurements of slope, but he does attempt 
to construct one. 

It is to be hoped that further observations may confirm the correct- 
ness of the very simple method proposed by Mr. McMath, which will be 
an invaluable practical advance if it should prove of general application. 

It was not the author's intention in the original paper to assert that 
the Kutter formula was under all circumstances reliable and accurate in 
its results. It is a great improvement upon all other general formulas, 
and the best we now have. 



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235 

General Ellis was connected with the Elmira case only towards its 
close, and seems not to have understood that no attempt was made 
on the part of the Lackawanna Company to obtain the correct discharge 
of the Chemnng Eiver by the application of the Kutter formula to the 
data mentioned by him, which were obtained at the site of the crossing. 
The general facts connected with the construction of the formula, were, 
indeed, introduced to show that the co-efficients applied to these data by 
the Erie experts, were by far too large, but the results presented were 
obtained at a different site, where the conditions were much more favor- 
able to an accurate gauging. 

It is true, the Lackawanna expert did contend that as the discharge 
of a stream is dependent upon several conditions and several relations 
of these conditions, reliable results can only be obtained by introducing 
the conditions and relations into the formula. If some complications 
result, the blame must be laid upon the stream which refuses to be 
governed by more simple laws. The complications too, are greatly ex- 
aggerated. The Chdzy form is adopted as being the most simple. The 
''complications" are confined to the formula for' the co-efficient, and 
may be avoided by the use of tables or the diagram. In addition to the 
operations required by the Ch^zy formula, eight others are required to 
obtain the co-efficient, and of the simplest character, such as can readily 
be computed in five to ten minutes. 

It is also true that much remains to be learned of the laws which affect 
the movement of running water. The empirical formula, however, now 
under discussion, makes no reference to those laws, but is based upon 
observations solely. The question is only as to its correct representation 
of those observations, and its applicability to similar cases. 

Neither is it correct to say that all formulas depending upon the 
slope and mean radius are indeterminate and misleading. The cases 
in which they are not applicable are rare. And although some author- 
ities do assert that the velocities vary with the sixth root of the slope, 
some with the fourth root, and others, by far the greater number, 
with the square root, the Kutter formula, containing the slope in 
the equation for the co -efficient, indicates that the relation between 
velocity and slope is a complex one, not to be represented by any single 
exponent. In rivers of small slope, and particularly in large rivers of 
that character, the exact determination of the slope is not easy, and 
results obtained from slope formulas are therefore more liable to give in- 



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286 

correct results, more especially as its relation to mean velooitj in snch 
cases is not so well determined. The position of the thread of greatest 
velocity does not appear in any of these formulas, and it may be higher 
or lower in the same vertical, without sensibly affecting the mean velocity 
of the section. 

It is asked why the Kutter formula for cement lined channels should 
not be applied to the Missisippi, supposing its bed plastered with cement. 
The reason is obvious. An empirical formula, based upon observations, 
cannot safely be applied to cases exceeding greatly the range of the ex- 
periments from which it was derived. The co-efficients of roughness for 
rivers in earthen beds, were derived from observations upon rivers both 
large and small, and they may be applied to all. Those upon cement 
lined channels were from experiments upon small channels only, none 
exceeding two metres wide, and their application to the Mississippi is an 
extension too far beyond the cases which served for their formation. 

The co-efficient of rugosity is criticized as being independent of the 
size of the stream, but this is not the case. Certainly n is invariable for 
each class or category, but being divided by %/i? in the formula for the 
co-efficient, it practically varies inversely as the square root of the mean 
radius, which represents the size of the stream. 

Kutter remarks that the Darcy-Bazin observations prove that the de- 
gree of roughness of the wet perimeter has a very important influence on 
the value of the co-efficient in small sections ; the proportions of their 
formula show that it decreases with increase of sectional area, and, 
although it never entirely vanishes, is inconsiderable in very large rivers 
like the Mississippi. 

Gen. Ellis correctly states the maximum discrepancy between the 
exact gauging made by Major Cunningham, and the results calculated 
by the Kutter formula to have been, at one site, from -f 19.5 per cent, to 
— 21 per cent., and at the other side -f 42.3 to — 14 per cent. Yet of 83 
observations and comparisons, including these exreme ones, the mean 
discrepancy was about 5 per cent. ; 70 observations differed not more than 
7^ per cent., and 50 agreed with the results of computation within three 
per cent. Moreover Major Cunningham remarks that many of the obser- 
vations which differed more than 10 per cent, from calculated discharges 
were not nearly so well determined as the others. 

The conditions quoted from Major Cunningham go to show, as might 
be expected, that the accuracy of the computed results will depend on 



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237 

the aooaraoy of the data. He refers to large canals because his experi- 
ments were made upon canals of that dass, and he limits his remarks to- 
the oases within his observation. The comparison of the results by this 
formula with gaugings of numerous rivers of Europe, as given inKutter's 
papers, show that its applicability is not limited to large canals. He 
correctly says that the Kutter formula is purely empirical, and only of 
limited and uncertain applicability—" limited " to the range of cases 
from which it was constructed, and ** uncertain" whenever those con - 
ditions are departed from. 

General Ellis' very careful and valuable experiments upon the dis- 
charge of Connecticut rivers, have been discussed by him as to the mean 
velocity on each vertical, its relation to mid-depth velocity, and the use 
of observed velocities to determine the mean velocity of the stream, but 
he has not published any comparison of his results with those given by 
any formula applied to the same conditions. 

Time has not permitted an analysis of these experiments with a view 
to the comparison of them with formulae containing the slope. A par- 
tial investigation discloses very great discrepancies, and indicates a 
possible reason for them. Tested by Captain Cunningham's conditions, 
the site was not a favorable one for this purpose however suitable for 
the object for which it was adopted.* It is situated in marked hollows 
in the bed slope. The water is from 8 to 18 feet deep when its surface 
is about level with the crest of Enfield dam which is 4 800 feet below the 
lowest section station, and one of the sections has a mean low water 
depth of but 3.2 feet. Applying the Ch^zy formula to some of the 
observations, the co-efficients are found to vary between the same sta- 
tions from 132 to 62, varying with the height of the water, and dimin- 
ishing rapidly as the height approaches low water. The discharges 
appear to vary nearly as the square root of the cube of the height 
above a certain point which is about 1.5' lower than lowest water re- 
corded. Many of the slopes are very small, a number of them are less 
than 0.1 feet in a distance of 6 200 feet, and they appear to vary, possibly 
with the wind, without corresponding influence upon the discharge. 
The case seems to be analogous to the two experiments of Dubuat upon 
the river Hayne, rejected by Humphreys & Abbot, because a lock inter- 

* Capt. Cunningham (Roorkee Ezpts., 1881), considers one of his Beira sites to be un- 
farorable, because the bottom is 2 feet lower than the sill of a bridge 1 800" above, and as 
much below the level of a dam 4 miles below it. 



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238 

mpted its flow and reduced it to a kiod of elongated basin, with an 
almost inappreciable slope. The relation of discharge to height of 
water surface resembles the law of discharge over a weir, and suggests 
their dependence upon the level of the dam or the bar below them. It 
will be observed that small as are the slopes, their effect is much less 
than would be indicated by Eutter's or any other slope formula, unless 
indeed the bed is very rough, which it is understood, was not the case. 

Mr. McMath has shown that these observations conform very nearly 
to his newly published law, that in certain (numerous) cases that 
velocity varies directly as the stage. 

The same results have been observed before in a similar case— that is, 
the Ch^zy co-efficient of velocity, has been found to diminish very 
rapidly and become very low, about the same as here, viz. : 62, when the 
stage approached lowest water. This upon a pool 10 miles long, 5 to 12 
feet deep at low water, closed at its lower end by a bar, having a narrow, 
shallow channel. 

The object of- the writer in the Elmira case was to get rid of the 
'* guess and allow," and *' average judgment" rule, and where positive 
data were not obtainable, methods were adopted, which would give maxi- 
mum results, such as could not be criticized by the opposing counsel as 
too small. 

But it cannot be admitted that where uncertainties are introduced in 
the data, it is best to adhere to the more simple form. If the data are 
good enough to warrant their use to determine the discharge, then the 
best results— results which will approach the truth in proportion to the 
accuracy of the data, will be obtained by their application to the actual 
conditions of the case. The older authorities, those preceding Darcy 
and Eutter use different co-efficients in the Ch^zy formula, some prefer- 
ring one, some another, and a few using two for different cases, varying 
from 68 to 100. Eutter uses the whole range between and beyond these 
figures, and defines the conditions which require their use. 

The references to Mr. Francis' results quoted by General Ellis are 
from the report of the Commissioners, and have no reference to the Eutter 
formula. 

Van Nostrand*s Magazine for June, 1882, contains a full discussion of 
some of the questions here treated, in a paper on the ** Obstruction to 
River Discharge by Bridge Piers, by General Q. A. GiUmore, U. S. Engi- 
neers," and is based upon the circumstances of the Elmira crossing case. 



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239 

This paper has been reviewed in ''Engineering News" of 17th Jane 
last, and the references by the reviewer to the present paper and its 
author, seem to justify a notice of them in this discussion. 

It is not proposed, however, to open any new points, or to repeat 
what has already been said. The interesting discussions upon the velo- 
cities of the stream and their power to move large stones, do not call for 
any notice, as it has been shown that the velocities could not be correctly 
obtained from observations made at the site, similar to those relied upon 
in the paper referred to. 

To determine the increased rise which would be caused by the con- 
traction of the waterway by the works of the Lackawanna Company, two 
formulas are used, which furnish very different results. The first is 
that of Eytelwein, the second is quoted from Debauve (Manual de V 
Jnginieur des Pants et Chausseea. Pants et Mafonnerie), but had long be- 
fore been given by D'Aubuisson. The great discrepancy in the results 
given by these two formulas (the rise y by the Eytelwein formula would 
be 2.3% by that of D'Aubuisson 4.3'), both of them founded upon the 
same general principle, has suggested an examination of the process by 
which they were constructed, which seems to be worth recording. 

Dubuat, with whom the method originated, assumes that there will be 
no considerable change of velocity in the section above the contraction. 
Ck)nsequently the velocity in the contraction will be to that above it^ 

inversely as the sections, v„=~ ^ — , and the difference of the heights to 

which these velocities are due will be y = — t^- == -„ o = -^ 

{- 1 J ; and the co-efficient which is to compensate for the con- 
traction of the stream in the narrow water-way is applied to the resulting 
height, so that in its final form we have y= ^^ T l\ . 

In the first edition (1801) of his Handbuch der Mechanik und der Hy- 
draulik, Eytelwein follows Dubuat in neglecting the diminution of the 
velocity above the contraction, caused by the raising of the surface, but he 
applies the correction for contraction to the narrow section only. Thus 

^^^^ = iC'!D-'tC^'m'(^*'-i)'^ being in this 
case V^ X 0.95. 



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240 



In the edition of 1843 of the same work he makes v„ = 



i>oQ 



vo Wh 



, vo^ / Wh \' 






— . or 






(«' (h+y) 



w(h+y) 
AS quoted by General Gilmore. 

It will be observed that vq being original mean velocity, v, 



(that 



between the piers) is not — j^ 
'^ ' w {h-\ 



Q 



_Vo WhvoW 

Again, as the second member of the primary equation is the head due to 

(Wh \ « 

h* 



t>o, 



,r-; — r- which does not vary with the co-efficient of contraction. 

Substituting we have y= o^- (— , «"~rA4- ^«/ ' ^ ^^g the usual 

co-efficient of contraction applicable to the character of the entrance to the 
contraction. This form involves smaller numbers than the formula quoted 
by General Gilmore from Debauve, but it is substantially the same. 

The discharge of the main river is computed by Darcy's formula, 
by that of Humphreys & Abbot, and by Eutter's, making in the last 
the coefficient of rugosity, n = 0.026 «*for large rivers," This is 
thought to be unwarranted by the circumstances, n does not depend on 
the size of the stream, but on the condition of the bed. Making 
n = 0.035 as for ''rivers and canals in bad order and regimen, overgrown 
with vegetation, and strewn with stones, or detritus of any sort," or 
'*with beds and banks in bad order having irregularities and deposits of 
** stone and much overgrown with vegetation " — with this value of n we 
have the volume of discharge 133 900 cubic feet— and the table given, 
when extended to include this value, and omitting the results of the 
Eytelwein formula for rise, will be as follows : 



Formal* for Velocity. 



Downing 

Bazin 

Humphreys — Abbot 

Ganguillet <b Kutter, n = 0.026 
do. do. n = 0.035 



Volame of 
Discharge 
Cubic feet. 


Formulft for 

Rise. 

Debaave 

(D'Aubuiuon). 


202.059 


4 8168^ 


197.698 


4.1118' 


181.578 


1.7587' 


161.010 


2.6775' 


133.900 


1.826' 



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241 

The map accompanying the paper is deemed to offer ample evidence 
of irregularities and vegetation, while the description of page 444 in- 
dicates detritus and deposts of stone. 

It will be remembered, also, that on the trial the Lackawanna Company 
claimed that these irregularities were such as could not be compared with 
any other stream which had been gauged under similar conditions, and 
that a reliable computation must be based upon observations at a place 
comparable with some experimental site. 

The reviewer in ''Engineering News,** referring to the Elmira case, 
says that the Lackawanna expert selected '' the bridge crossings at Elmira, 
** of which there are three of varying lengths, and a mill dam, in the dis- 
'' tance, on the river of little over half a mile. » * * Whether 
''he used one bridge or all three, or the slope resulting from the 
"combined obstacles of the locality, or finally what was the degree of 
"roughness allowed for in the Kutter formula," * * he does not 
know. As the points mentioned were given in the evidence they could 
easily have been ascertained. It is hardly necessary to say that tliese 
insinuations are uncalled for. The observations were made in an unob- 
structed, straight portion of the channel, and the co efficient of rough- 
ness selected after careful examination of the site and comparison with 
other rivers, was that of Kutter*s second class of earth channels, such as 
are in moderately good order in .every respect, 0.030. The distance 
between sections was less than would have been preferred, but the data 
were by far the most reliable to be obtained. 

The review contains extracts from an article in "Engineering** 
(quoted from Van Nostrand's Magazine of 1873, p. 320), which is said to 
show that the invariable co-efficients of the older authors are incorrect, 
and that C should vary with the discharge of the stroam. Those in- 
terested are referred to a more recent editorial in the same able paper 
. on p. 517, of voL XX, 1875, which is too long to be quoted here. 



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AMEBIOAN SOCIETY OF CIVIL ENGINEERS. 

INSTITUTED 18S2. 



TRA.JSrS^OTIOJSrS. 

NoTB.~l*his Society is not responsible, as a body, for the facts and opinions advanced in 
any of its publications. 



CCXLI. 

Vol. XI.— July. 1882. 



ACCURACY OP MEASUREMENT AS INCREASED 
BY REPETITION. 



By Stephen S. Haiqht, Member of the Society. 
Pebsented at the Annual Convention, Mat 17th, 1882. 



Probably most of the instruments in use for the measurement of 
angles are so graduated that the smallest reading that can be made witk 
them is one minute. 

Although this is a great advance upon the old compass, divided 
into quarter degrees, it still permits errors much too large for careful 
surveying, if means are not provided for securing greater accuracy. 

This provision is made by repeating the measurements. 

In the work of surveying and monumenting the new streets of New 
York City, the limit of error is five seconds per angle and fifteen one- 
hundredths of a foot for each one thousand feet of measured traverse, as 
found by calculation ; yet there is little difficulty in keeping within this 
limit with a twenty -second transit and a chain adjustable for tempera- 
ture. 



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243 

The repetition of the linear measurements is simply for each chain 
length, until the forward chainman becomes satisfied that the centre of 
hia pin, where it enters the ground, is precisely beneath the point of his 
plnmb bob, the pin being so placed as to be at right angles to the line 
and in as near a horizontal position as it can be made firm. 

The short measurements with a steel pocket tape are made level hj 
means of running one end up and down a plumb line and repeating 
the process until the shortest distance between two fixed points is 
obtained. 

Horizontal measurements with the chain are secured by means of a 
level bubble attached to one end of the chain and forming a part 
thereof. 

Six repetitions are usually made of the angular measurements, but 
not by computing the mean of six independent readings. 

With the vernier at zero, the vertical hair of the telescope is carefully 
placed so as to cover the left hand point, with the instrument clamped ; 
then loosening the vernier, the glass is turned toward the right and is 
fastened so that the second point is covered by the hair. 

The reading being noted, the instrument is undamped and turned to 
the left and made fast so that the vertical hair again covers the starting 
point. Upon loosening the vernier and turning the glass so as to again 
cover the second point, the second measurement has been made from the 
end of the first, instead of afresh from zero, and if the vernier is read ii 
will be found to be approximately twice that first noted. 

It is not advisable, however, to read the limb after noting the first 
measurement until the close of the sixth, when the reading, being added 
to the number of complete circles that may have been turned, and the 
sum divided by six, the quotient may be accepted as the size of the angle. 

This, in good work, will always be within twenty seconds of the first 
reading if a twenty second instrument is used, or within one minute if 
the instrument reads only to minutes. 

The measurement so obtained is incomparably more reliable than the 
average that is deduced by dividing the aggregate of six separate read- 
ings by six. 

The principle of this method may be illustrated by linear measure- 
ment, as shown on the diagram, page 250. 

It is desired to measure the distance between two points that are 
three centimetres apart, giving the distance in ten-thousandths of a foot,^ 



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244 

the smallest sabdivision of the scale being one one-hundredth of a foot 
in length. 

As three centimetres are equal to a very little more than nine hun- 
dred and eighty-four ten-thousandths of a foot, the tost reading will be 
a little less than one-tenth of a foot, and the measurement cannot be 
made more nearly by any number of independent readings. 

The desired result can be easily effected by taking the distance be- 
tween the points of a pair of dividers and carefully stepping six times 
along the scale from zero. The end of the sixth step will be a little 
beyond fifty-nine one-hundredths of a foot ; the quotient obtained by 
dividing this by six is nine hundred and eighty-three and one-third 
ten -thousandths of a foot, which differs less than one ten-thousandth 
of a foot from the actual length of three centimetres. 

Owing to unavoidable errors in all instrumental work, it is rarely the 
case that the angular closing of a polygon will be precisely in accordance 
with theory. 

The probable error in the measurement of each angle can be calcu- 
lated by apportioning the aggregate error of the polygon among all the 
angles, with a closer approximation to the truth than by the use of any 
set formula. 

In making this apportionment it should be remembered that the 
shorter the radius the greater the liability to angular error, and it would 
seem to be most in accordance with ^ood judgment to make the greatest 
correction in that angle whose sides are the shortest. 

The calculation of the co-ordinates of the several stations of the poly- 
gon, or of their latitudes and departures, will sometimes show that a 
proper balancing of a survey will require that the whole aggregate angu- 
lar error of the polygon should be corrected in some few of the angles 
while others are taken as measured. 

A simple method of testing the accuracy of angular measurements is 
by adding together all of the interior angles of the polygon (the supple- 
ments being used of those measured exteriorly). 

Whatever the aggregate may differ from an exact multiple of ninetj 
degrees will, of course, be the error of the polygon, and the quotient 
arising from dividing this error by the number of angles measured will 
be the error per angle, which may be corrected as previously stated, if 
less than five seconds. 

In dividing a large block into smaller ones by cross lines it is often 



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2d6 

found that the aggregate angular errors of one of the subdivisions is plus, 
while those of the adjoining block are minus, so that a judicious cor- 
rection in balancing will improve both. 

Sometimes there will be little error in the angles of a large polygon, 
while the excess in one of its subdivisions and the deficiency in another 
will be each greater than the allowable error. 

Where this is the case the angles of the cross line should be re- 
measured. 

On the accompanying map, (Plates XXII, XXHI,) which is a plan of 
streets in a part of the Central District of the Twenty-fourfh Ward of 
New York City, the traverse lines are shown, dividing a block into four 
smaller ones, with the size of angles and lengths of lines as actually 
measured. 

The readings of each angle are given (and the mode of testing as de- 
scribed for each block) on separate sheets, pages 249 and 250, and Plates 
XXIV, XXV. 

A table is also given of the calculation of co-ordinates of the traverse 
stations ; station fifteen being used as the initial point and the line from 
station fifteen to station one being assumed as north. 

All but four of the stations of this survey are on rock or large 
boulders, the station being at the intersection of two fine lines cut with 
a chisel in the form of a rectangular cross. 

The lines connecting stations, the numbers of which are underlined, 
form portions of blocks that were surveyed in October, 1881, and were 
connected with the other stations, as shown on the map, in February, 
1882. 

Such accurate work will, of course, require more time for its perform- 
ance than surveys of a rougher kind, and it may be of interest to state 
that the writer with two chainmen was engaged seven days in February, 
1882, upon the surveys here shown. The establishment of points and 
clearing of lines took considerable of this time, and the ground being 
covered by deep snow made the progress slower than it would otherwise 
have been. Under more favorable circumstances the same party has fre- 
quently measured more than half a mile in a day, so that the survey 
would close with less errors than would have been allowed. 

Occasions constantly arise where it is necessary to establish points at 
a prescribed distance and angle from some other point and line. 
The repetition of the measurement of the angle is here of great service. 



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246 

The desired angle being approximately tamed, a stake is firmly 
driven on the line, at some point where its top will be visible from the 
transit, and (if practicable) at a distance found by pacing to be some- 
what in excess of that prescribed. 

A pin or match being firmly placed in a vertical position on the top 
of the stake, on the line as given from the transit, the angle is carefully 
measured with six repetitions, as previously described. 

The difference between the prescribed angle and one-sixth of this 
last reading will be error, which may be corrected by moving the pin or 
match to the left or right, according as the error may be plus or minus, 
a distance equal to the product of the sine of the error multiplied by 
the distance of the stake from the transit. 

The sine of sixty seconds being approximately thirty-one hundred 
thousandths, a simple and easily applied mode of correcting the error is 
to multiply half the number of seconds in the error, regarded as hun- 
dredths of a foot, by the number of feet that the stake is distant from 
the transit, expressed as thousandths. The product is the distance that 
the pin must be moved at right angles to the line to place it on the pre- 
scribed line. 

When the distance is short a less number of readings than six may 
be taken. 

As the error will seldom be as large as the smallest reading that can 
be made with the instrument, and the line rarely more than two hun- 
dred feet in length, this mode is practically accurate, even with the 
correction based upon the distance being obtained by pacing. 

This proposition may be demonstrated as follows, viz. : 

Twenty seconds error would appear by this rule to cause a departure 
of ten one-hundred ths of a foot in one thousand feet; or two one-hun- 
dredths of a foot in two hundred feet. 

This differs less than seven ten-thousandths of a foot from the cor- 
rection that would be obtained by using the sine to the seventh decimal 
place. 

With an error of twenty seconds in the angle a difference of ten feet, 
more or less, in the distance would make a difference in the departure 
(or distance to move the pin) of only one one-thousandth of a foot; 
therefore when the distance is short it can be obtained by pacing with 
sufficient accuracy for correcting the angle. 

It is safer, however, to roughly measure the distance that may be in 



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^XLKllh3fc 



,€^XLyiU-'i7 




PLATE XXIII 

TRANS AM. SOC Cl\ FNGRS 

VOL. XI No.CCXL. 

HAIGHT 

ON MEASUREMENTS. 



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247 

excess of that which was prescribed, which last will, of course, be meas- 
nred with care; and if the angular error exceeds twenty seconds its true 
sine should be used as a factor in obtaining the correction in all cases 
where the distance is as great as two hundred feet. 

This method of applying the repetition of measurement of angles to 
the establishment of prescribed points is shown on the accompanying 
paper of instructions for setting monument points. The writer's first 
. use of the method was in establishing points in topographical surveying 
on a rectangular basis, in the summer of 1871, when the result of its use 
was so satisfactory as to cause its employment constantly since that 
time. 

The repetition of measurement of angles in the manner described 
has been in constant use in the Department of Public Parks of New 
York City for at least twelve years, and, the writer believes, was prev- 
iously used in the survey of Morrisania, and afterward in Long Island 
City, in Yonkers and other places. Its value is so great that no surveyor 
who has once become familiar with the system will willingly dispense 
with it where accurate work is required. This refinement of surveying, 
as it may be termed, is little better than farcical affectation if certain 
preliminary essentials are not observed. 

Of these, one of the most important is the standard of measurement, 
and every engineer should endeavor to supply himself with one that is 
correct. Having obtained a measure that is believed to be accurate, it 
should be applied to the establishment of points that will be as nearly 
as possible unchangeable, so as to make a permanent standard for test- 
ing and correcting. This will make it possible to have all his work con- 
sistent with itself, even though he should not succeed in getting an 
absolutely correct standard. 

The transit or theodolite must, of necessity, be correctly graduated, 
and be kept in good adjustment. Many instruments have been made 
with the plumb bob suspended from the head of the tripod; this may 
do for some work, but not for such as is described in this paper. The 
tripod head must be open, so that the plumb line can be attached directly 
to the instrument, and the plumb bob must be accurately turned. 

In windy weather an essential for accurate work will be the shielding 
of the plumb line in setting the transit and in placing a line for meas- 
urement of angles, as well as in chaining over irregular ground, all linear 
measurements being made horizontal. 



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248 

The last of these essentials to mention, although first in importance, 
is oare in work, reliable ohainmen being indispensable. 

In angular measurements it will be well to always use the same vernier, 
and to always measure from left to right. An imperceptible movement 
of the instrument when turning the upper or inner plate will sometimes 
be indicated by the readings. This may be remedied or balanced by 
turning the glass toward the left for some of the repetitions. Where 
the first reading is as large as one hundred and fifty degrees the glass 
should be turned to the left as many times as to the right; but for one 
hundred and twenty degrees twice to the left will balance four times 
to the right, while for ninety degrees or under, once to the left will be 
sufiScient for the six readings or repetitions. 

The tests that have been hereinbefore described will not apply where 
tracts are not wholly enclosed; and it is, therefore, well that such strict 
accuracy is not ordinarily required in the survey of long lines, as for 
railroads or country highways; yet, even there, it will be of advantage 
to take two readings of each angle as a check against error. 

An occasional noting of the magnetic bearing will also serve as a 
check that should be availed of, for in no profession can guards against 
error be less safely dispensed with than in that of civil engineering. 

The amount of care that is taken in surveying is frequently governed 
by the opinion entertained regarding its reasonable cost. 

The writer is acquainted with a surveyor, for whom he has a high 
respect as a worthy, conscientious man, who, though possessing an 
excellent transit with verniers reading single mintites, yet makes all his 
surveys by the needle, objecting to the use of the limb because **it 
would require the taking of back sights,*' which would make him feel 
as though he was ** nursing the job." 

For such surveying, even where not affected by local attraction, the 
amount of error allowed by Professor Gummere, of three links in ten 
chains, or three feet per thousand feet, is none too large. 

A motto particularly worthy of acceptance by all engaged in the 
practice of the profession of civil engineering is ** What is worth doing 
at all is worth doing well." 



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REP6T\T|0N of ANaULAK MeAauHSMfi-WT 
IN SST^eLt^HlNU NlONOIWeNT "POINTS. — 

PoTTci^. Place 



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wiCiLuM. IOC , / 







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rfiiHM'Uc 



VULVMI 




WooPLAwN Road 






*ux-a4 




XLyi#i-32^ 







PLATE X/:V. 

TRANS. AM. SOC. CIV. ENGR '^ 

VOL.XI.No.CCXLI. 

HAIGHT 

ON MEASUREMENTS. 



l>t«.VlM-l<J 

1^ ^BAflNQRmcE AveJ V 

CAUCULATET D POSniOWS 
OP (V\OlV\U MEMTS 



%Li^kO 



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249 

Bbadinos of Anolbs. 



16a W 29' 20' 1 148° 42' 20" la 64** 88' 20' 
6)266 64 40 6)862 14 20 6)327 60 00 



VO'' 27'06".7 \ir 4(/ 16'.7 



44" 29' 06'.7 UZ" 42' 28'.3 64*' 88' 20' 

2 107^* 60' 40" 2a 61° 07' 20' 2^ 69° 48' 00" 
647 02 40 366 43 40 358 18 20 



107° 60' 26'.7 61° 07' 16'.7 69° 48' 05'.a 

3 80° 49' 00" 3a 69° 09' 40' 4 184° 48' 40' 
484 64 20 354 67 00' 808 63 20 



80° 49' 03'.3 69° 09' 80' 134° 48' 53'.3 

4a 161° 21' 20' 6 98° 10' 40' 7 116° 64' 40' 
908 08 20 689 03 40 701 28 40 



161° 21' 23'.3 98° 10' 36'.7 116° 64' 46'.7 

7a 129° 11' 40' 8 124° 56' 00' 6 126° 09' 40' 
775 11 20 749 31 00 766 68 20 



129° 1 1' 63'.3 124° 66' 10' 126*' 09' 43'.3 

9 99° 06' 20' 10 89° 26' 00' 10a 66° 20' 40' 
694 39 20 636 37 20 398 04 00 



99° 06' 33'.3 89° 26' 13'.3 66° 20' 40' 

11 165° 25' 40" 12 152" 24' 00' 13 171° 05' 00' 
992 88 20 914 24 20 1026 29 00 



165° 25' 33'.8 152° 24' 08'.3 171° 04' 60' 

20 53° 40' 40' 15 152° 28' 00' 16 163° 41' 00' 
322 02 20 914 47 20 982 06 00 



63° 40' 23'.3 162° 27' 53'.3 163' 41' 00' 

16a 70° 27' 20' 19 179° 40' 00' 

422 42 40 1078 01 40 



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Tests of Aocuuaot of AmouijAB Meabubememt. 





----- - - - 


- 




^ 




Block 942'. 




Block 942. 




< 2 = er or i6'.7 


< 2 


= 107° 60' 26'.7 




2^= 69' 43' 03'.3 




1 


= 161° 39' 16'.7 




3 r= 6r 09' 30" 


Supt. 


12 
11 
10 


= 162° 24'03'.8 
= 14° 34' 26'.7 




179" 69' 60' 


= 89° 26' IS'.S 




3 < —10". 




9 

7 


= 99° 06' 33'.8 
:= 113' 63' 20' 




Block 941. 


Supt. 


8 


=; 66° 04' 60' 




< 6 = 126° 09' 43'.8 


Supt 


6 


= 63° 50' 16'.7 




8 = 124° 66' 10' 




4 


= 161° 21'23'.8 




7 = 116°64'46'.7 




8 


= 80°49'03'.3 




6 = 98° 10' 36".7 
4 = 78° 49' 43'.3 














1079° 69' 63'.8 
14 < — 06'.7 




640** 00' 00' 




6 < No apparent error. 










Block 949. Block 






928, Errors = -lO'.O 


< 


1 = 64" 88' 20" 
16 = 163° 08' 00' 
16 = 126" 51' 53'.o 






941, •• = OO'.O 

942. •' = -06'.7 
949, " = -h06'.7 




19 = 179° 40' 16'. 7 


942 and 942', " = — 16'.7 


Supt. 


20 = 126° 19' 36".7 


942, 941 and 942', '* = — 16'.7 




13 = 17r 04' SO"^ 


942, 942' 


and 949, " = —lO'.O 




10 = 66° 20' 40' 


942,941,942' 


'and 949, " = —lO'.O 




11 =^ 165 26'33'.8 


941 


and 942. ** = -06'.7 


Supt. 


12 = 27^ 35' 66\7 


942 and 949, ** = OO'.O 
941, 942 and 949, " = OO'.O 




1080° 00' 06'.7 


11 < 


. + 06'.7 









jlCgmiiMutax— 

* .00M3 *jrr 



=1 



Og»» — 0.09833 +;t. 



1 1 1 1 1 1 1 m | 1 1 i 11 1 1 1 1'l 1 M 1 1 1 1 1 1' j^i 1 1 1 1 1 1 1 II ' 1 1 1 1 1 1 1 n 1 1 1 1 1 
j! 1 1- 1 1 



1 1 1 1 1 1 1 1 1 1 






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IStol ' 

< w. sft" irst'.i 

1 to2 

< E. 72"'09'88'.8 

2 to 8 , 

< S. W. 80M9'08*.8.. 

8 to4 

< N. E. 184M8'68'.8.. 

4 to6 

< S W. 98° lO'Se'.Y.. 

6to7 

< E. 60M8'06'.7 

7 to 9 

< W. 80° 68'26\7 

9 to 10 

< W. 24° 13'06".7 

10 to 18 

< W. 8° 65' lO'.O 

18 to 20 

< N. W. 126° 19'86'.7. 

20 to 19 

< E. 00° 19'43'.8 

19 to 16 ■ 

< E. 64°08'O6'.7 ' 

16 to 15 

— ♦ 

< E. 16° 67'00'.0 

< W. 28° 88'86'.7 

4 to5 

< E. 63° 60' 16'.7 

6 to8 

< N. E. 124° 66' 10* 0. . 

8 to7 



< W. 63° 06' 13'.3 



< S. E. 64° 88' 20'.0. . j 

I to 12 4 

< E. 27° 86'56'.7 4 

12 toll 

< S. 14° 84' 26*7 

II to 10 



< N. 89° 26' 13'.8. 



< N. W. 61° 07' 16' .7. i 

2to2i i 

< E. 69°48'03'.8..... 

2ito8 J 



< S. W. 59° 09'30".0., 



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AMEMOAN SOCIETY OF CIVIL ENGINEERS. 

INSTITUTED 1862. 



TR^N 8i?LOT10]Sr8. 

NoTB.— ThiB Society is not re«ponsibIe, ae a body, for the factn and opinions advanced in 
any of its publications. 



CCXLII. 

(Vol. XI.-Angnst. I»82.) 



THE OVEHPLOW OP THE MISSISSIPPI KIVEB. 



By Lyman Bbidgbs, Member A. S. 0. E. 
Bead Mabch 15th, 1882. 



With Discussions by E. L. CoRTHBLii and J. A. Ookebson, 
Membebs a. S. C. E. 



Much has been written, and many theories advanced by distinguished 
engineers, daring the last twenty -five years, upon the levees, jetties and 
floods of the Mississippi. 

This grand river, called the ''Father of Waters,'' like the trunk of a 
tree whose branches extend from the Bocky Mountains on the west, to 
the Alleghanies on the east, and to Canada on the north, drains a water- 
shed of 1 147 000 square miles, extending over fourteen States, or an 
area nearly as large as the whole of Europe, with an annual downfall 
(exclusive of the Red River basin) of eighty trillions (80 000 000 000 000) 



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of cubic feet of water, and a drainage of twenty trillions cubic feet, or a 
ratio of twenty-five per cent, of the downfall per annum. 

Admitting that the downfall and drainage are the same now as 
twenty-five or fifty years ago, new problems and new conditions present 
themselves. 

The immense area of forest and timber lands cleared and the ad- 
ditional acreage placed under cultivation in the basins tributary to the 
Mississippi, necessarily change the rapidity of the drainage, and the 
increase of sediment in time of floods. 

Another feature of no small moment is the gradual straightening of 
the river, which, during the last 160 years, has shortened its course 240 
miles between Cairo and New Orleans; this increases the rapidity of 
the current and helps to overtax the levees below. 

The vast swamps, bayous and lakes on either side of the Missis- 
«ippi above the mouth of the Bed River, are inundated and overflowed 
at the beginning of each season of high water, forming reservoirs for 
the surplus water of the river, thus relieving to a certain degree the 
lower Mississippi from its incapacity to carry off the water before it has 
reached the flood stage. 

The great rainfall and water-shed of this river and its tributaries, 
equals a basin of water four hundred miles long, forty miles wide 
and 160 feet deep, and it would take tha bed of the Mississippi, at 
the present rate of the current, three years to carry this water to the 
Gulf ; or taking the ratio of 25%, which is universally admitted, had 
it an average daily drainage, it takes nine months of the year at its 
maximum to carry off this immense volume of water. But when we 
consider that the overflowed reservoirs on either side of the river, 
once filled, represent a volume of water nearly fifty miles in width and 
twelve feet deep from Cairo to New Orleans, or about twelve billions 
(12 000 000 000) of cubic feet of water, which would take the maximum 
capacity of the Mississippi eighty-four days to carry away, even though 
it had no reinforcement constantly forced upon it. above, it is conclusive 
that no system of levees, below Bed Biver, thus far constructed or pro- 
posed, can take away this yearly inland sea, having but 322 feet of fall 
from Cjdro to the mouth of the Mississippi, and whose current is in- 
creased in flood stages from one-half mile an hour at medium stages to 
three (3) miles per hour and 1 000 000 cubic feet per second at flood 
stages. Some other means must be provided for the overflow above the 



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maxiinum capacity of the river. The principal levees are below the 
month of the Bed Biver, and the capacity of the channel below that 
month has been largely increased by the costly levees on either side. 
It is compelled to attempt not only to carry off this immense volume 
of water, but in case of flood both above and upon the adjacent country 
through which it passes, it has always been taxed to its utmost capacity, 
and it has been unable to escape injury and iaxpensive crevasses, in- 
flicting untold injury upon the surrounding country. 

Added to this area is the country tributary to the Bed Biver, com- 
prising an area of 97 000 square miles, with an annual downfall of 
8 800 000 000 000 of cubic feet, and an annual drainage of 1 800 000- 
000 000 cubic feet of wetter. 

The water from this immense additional water-shed, and the additional 
sediment necessarily carried down the Mississippi thereby, must be pro- 
vided for in some other way. We are informed by Gens. Humphreys 
and Abbott, who gave years of study to this subject, that the mean 
annual discharge of the Mississippi proper was 19 500 000 000 000 cubic 
feet and 812 500 000 000 tons of sedimentary matter, constituting 241 
feet in depth, one mile square, passing the mouth of the Bed Biver 
annually. 

When such is the case, the river must necessarily deposit a part of 
that sediment in the portions of the river the least direct, and thereby 
render the levees less efficient, until by a continual raising of the levees, 
the bottom of the river will be as it is in some instances now, above the 
level of the lands adjoining. 

Over 8100 000 000 has been expended in the construction of the Mis- 
sissippi levees already. 

During the past fifteen years over 100 miles of levees have caved in, 
and been lost to owners and the country. 

How can we remedy the present evils and provide for the increased 
volume of water and future floods ? 

We claim that the overflow has never been carried off by the Missis- 
sippi, and that its maximum capacity in time of floods never can be the 
medium or channel of the overflow at the flood stage, without many 
years of labor and great expense in deepening the river channel, and 
that the old natural channel or cut-off via the Atchafalaya Biver should 
be the main channel of relief aided by the Placquemine Bayou to the 
Atchafalaya, and the Bonnet Oarr€ to Lake Pontchartrain. 



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254 

The old channel of the Mississippi near the mouth of the Red River, 
near WiUiamsport, above Morgan's Bend, and the Atchofalaya River and 
Bayou from its connection with the Red River above its mouth, should be 
improved and a connection made with the old channel of the Mississippi 
through Latanache Bayou to Morris* Bay at Atchafalaya River and 
Bayou, thence through Bayou Alabama, Whiskey Bay and Grand River, 
Lake Rond and Grand Lake.* 

Thence through Atchafalaya River to Atchafalaya Bay on the Gulf 
of Mexico. (See accompanying Plate XXVI.) 

Also Grand River should be connected with Placquemine Bayou and 
the Mississippi at Placquemine, between Baton Rouge and Donaldson- 
viUe. 

By this Atchafalaya River and Bayou route, it* would be but one-half 
of the present length of the Mississippi to the Gulf of Mexico (from the 
mouth o^ he Red River), and only one-quarter of the distance by the 
Grand River and Placquemine route, and only about one-half of the 
distance would have to be improved, in either case, and the problem would 
be substantially solved, as the overflow would be confined to regular 
channels, and vast tracts of valuable lands reclaimed thereby. The 
elevation at mouth of Red River is 54 feet above the level of the Gulf of 
Mexico. Already steamers take the Atchafalaya route from Red River 
to Atchafalaya Bay, on the Gulf of Mexico, thus aiding commerce, f 

A controlled communication can be opened by a system of locks of 
sufficient width and depth at the old channel of the Mississippi, near 
the mouth of Red Ri^er, below high water mark for the Mississippi, 
sufficient to receive 33 per cent, of the Mississippi A system of locks 
above the mouth of Red River, with locks also in that river where the 
present channel would be turned into the Atchafalaya, would provide 
for navigation between the Red and the Mississippi. Continuing the 
channels to the Atchafalaya Bayou and River, and improving that and 
the other above mentioned bayous to Grand Lake, which would be but 
50 miles, not only the surplus water of the Mississippi, but also all of the 

* Already the oyerflow of the Mississippi and Red River have increased the channel of 
the Atchafalaya since 1850, between the bayous en route, ftom a width of 730 feet and a 
maximum depth of 52 feet, to a width of 1,200 feet, and over 100 feet in depth, or about 300 
per cent, increase, and this in the &ce of everything being done to direct all the waters of 
the Mississippi and Red Rivers through the channel of the Mississippi. 

t Recently Capt. N. Eastman took a steamboat from Chicago via Illinois and Michigan 
Canal and Mississippi River by this route to the Gulf of Mexico. 



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of 






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\ 

\ 
\ 



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T. 







DELTA 



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255 

Bed River (33 per cent, of the present water), would be conducted through 
this new channel to the Gulf of Mexico, in times of flood, for all time, at 
no greater expense than the cost of repairing the levees below the Red 
River for the present year. The locks at the mouth of the Red River 
and the sources of the Atchaf alaya River can be controlled so as to turn all 
of the Mississippi and Red Rivers through the Mississippi at low water 
or when desired. The Grand River and Placquemine Bayou connection 
by sills with Grand Lake and the Mississippi would also assist in carry- 
ing off any local flood, and assist in case of extraordinary flood in keeping 
the water within the levees, in addition to which, the Bonnet Carr€ out- 
let 40 miles above New Orleans could be improved and controlled by sills, 
for emergencies and extra high floods, conducting surplus flood water 
into Lake Pontchartrain. 

We claim that a regular controlled volume of water retained as nearly 
as practicable at its maximum, gives less friction, a regular or steady 
velocity, and consequently less deposits of sediment than by the present 
overtaxing of the levees. And crevasses are constantly occurring at all 
flood stages. At every crevasse bars form immediately below, and 
change the bed and slope of the river. This system of relief from the 
overflows is immediate, and would prove a great factor and auxiliary in 
any plan for deepening the river subsequently. 

The mistaken idea that the overflows help to scour the Mississippi 
River is answered by the fact that the Mississippi only takes its maxi- 
mum in any case, and a systematic control of the waste or present over- 
flow does not affect the scour or jetties at the mouth of the Mississippi, 
to their disadvantage. 

As more than half of the water that passes the mouths of the Mis- 
sissippi escapes through other channels than the pass where the jetties 
have been constructed, if the permanence of the present jetties and ship 
channel depends upon the scour of the river, matresses or jetties can be 
constructed across the other passes, and this surplus water confined and 
turned through the desired channel. 

La addition to the great benefits accruing to the country below the 
mouth of the Red River, these cut-offs would very materially reduce the 
height or depth of the Mississippi above the junction of the Red River, 
as far as Memphis at least. 

Another beneficial result would accrue from the systematic control 
of the overflow; that of the health of the citizens living upon and in the 



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Tioinity of these vast tracts of overflowed lands, who would escape the 
periodical epidemics, etc., that resnlt from the miasmatic atmosphere 
generated by these overflowed lands. 

The Mississippi River, with all its benefits to the commerce of the 
country, has never been completely surveyed by the United States, and 
maps made thereof, showing i|» main channel and tributaries. If this 
had been done, many of the citizens and sufferers by the present floods 
would have profited by such information, and comprehended the mag- 
nitude of this water question, and been better prepared to protect 
themselves. 

A State like Louisiana, with an area of 43 000 square miles, one-half 
of which would derive great benefits from such improvement, and a 
people raising such immense crops of cotton, sugar, rice, tobacco, and 
sugar cane for molasses, etc., which are now jeopardized and uncertain, 
would thereby be protected, and their crops assured, to the great benefit 
of the State and nation. 

A commission has recently been appointed to consider this and all 
other subjects pertaining to the commerce and improvement of the 
Mississippi River, and it is hoped that they will give this subject their 
careful consideration. 

Discussion at the Annual Convention by E. L. CoBTHBiiL, Mbmbeb 

A. S. 0. E. 

Mr. Chairman : — Many of the principles and statements advanced in 
this paper, are so directly opposed to my own experience on the Missis- 
sippi River, that I cannot refrain from making a few remarks. 

Those that are interested in, and have studied the phenomena of the 
Mississippi River, are divided into two camps ; one of which advocates 
the Outlet theory, and the other the Jetty theory, or rather the Disper- 
sion and the Concentration theories. 

The subject is of such vast importance, not only as an engineering 
question, but as regards the commercial and agricultural interests of the 
whole country, that it is necessary that the correct principles which 
underlie the improvement of the Mississippi River, should be thoroughly 
understood and appreciated. We must recollect at the outset, that the 
valley of the Mississippi which is drained by the main river, contains 
about 768 000 000 acres of the finest land on the face of the globe, enough 



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257 

to make more than one hundred and fifty States as large as Massachu- 
setts ; that if populated as Belgium and the Netherlands are (which 
may be the case at some future time), it would contain 400 000 000 of 
souls — nearly one-half the entire population of the world. 

This river, on the improvement of which engineers are so radically 
divided, is really the great artery of the Bepublic ; its branches envelope 
the great body of our country, and through its channel for all time to 
come must circulate the sustenance of our people. There is no doubt 
that the commerce of this great empire of the Mississippi valley, will in 
time exceed that of any other in Christendom. The channel which is, 
and must continue to be the natural highway not only of intercommerce 
among the states, but with the world outside, must have applied to it 
the correct principles of rectification. 

As between the two camps mentioned, my experience on the Missis- 
sippi River and its mouth, compels me to join myself to those that ad- 
vocate the concentration of the waters for the purpose of deepening the 
channel. The paper which we are discussing, advocates the dUpersion 
of the waters. 

Before commencing the discussion of the subject it is necessary to 
state to the Convention, that the laws which govern the flow of waters and 
the regulation of that flow in rivers whose waters ar6 clear, are entirely 
different from those we flnd in waters filled with sedimentary matters. 
However experienced and learned the engineer may be in the improve- 
ment of the dear- water streams or rivers, he finds when he commences 
upon the improvement of sediment-bearing rivers that he has new prin- 
ciples to deal with and new problems to solve, new and strange condi- 
tions meeting him at every turn. It will be necessary to divest ourselves 
of much of the experience we have gained in clear streams in order to 
fully appreciate the difficulties in the way of the improvement of a riyer 
like the Mississippi whose waters are more or less charged with sedi- 
ment ; we not only have the waters to contend with, but the fine detri- 
tus, which has come into the main channel from its innumerable tribu- 
taries, from mountains and plains whose rocks and soils are diverse in 
character. These heavy particles or washings from mountain and plains, 
being borne to the sea by the current which, by its velocity and its ir- 
regular motions suspends and carries forward its load, complicates the 
question of the improvement of the channel. The laws which govern 
the currents and the motions of the sediment are as variable as those 



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258 

which goyern the currents of clear water streams, but we find that all 
the forces of sediment bearing streams are in such perfect and delicate 
equilibrium, that the slightest attempt by man to disturb this equilibrium 
is liable to cause injury rather than benefit to the channel if the laws 
and forces are not throughly understood. We have noticed this particu- 
larly in our experience at the head of the passes of the Mississippi 
River, where in order to deepen the channel from the main river into the 
South Pass it was necessary to disturb this equilibrium of the current 
and sedimentary forces. The natural conditions existing there were so 
delicately adjusted, that any artificial change in any one of them pro. 
duced changes in all the others either for good or evil ; in fact there is 
not anything in nature more sensitive than the delicate adjustment of 
these mighty forces. 

It was my hope that we would be able to listen this evening to a dis- 
cussion on this paper by Captain Jas. B Eads, Vice-President of the 
Society ; he, we all know, has had many years of experience in the im- 
provement of the Mississippi River, and has given the subject careful con- 
sideration and study, but sickness prevents his attending the Convention, 
and it is by his wish that I present not only my own views but his also, 
with which I mdbt decidedly agree. He has handed me a paper which 
is a report to the Mississippi River Commission, and which contains not 
only his own views but those of the Commission also. The views are 
so dearly and concisely expressed and are also so exhaustive that I ask 
permission of the Convention to give them. The remainder of my dis- 
-cussion of the subject will therefore be extracts and abstracts from, and 
my comments on, this report. 

It is generally known that the Mississippi River Conmiission^ as soon 
as the necessary means were placed in its hands, went at the work in 
earnest to obtain the facts from which could be deduced the laws which 
govern the flow of the river, and which should become the basis for its 
proper improvement. From Cairo to New Orleans their hydrographic 
and topographic and levelling and transit parties have carefully 
gathered together a great many, if not all of the facts that are neces- 
sary for the purpose of studying the subject. The most careful and 
patient observations have been made by their parties to ascertain the 
efiTeots of crevasses and outlets, and also levees, dikes and jetties. The 
observations made by the Commission plainly show that the efiects of 
crevasses and gaps in levees have been to raise the flood line of the river 



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259 

above any height previously attained ; and the observations further 
show that between Natchez and the mouth of the Ohio River the de- 
posits of sediment, due entirely to these crevasses and gaps in the 
levees, have raised the bed so much as to injure navigation. 

We will now state the general principles which underlie the ^lan of 
improvement recommended by the Commission, and which were the re- 
sult of the observations made, the facts obtained, and the thorough and 
close study given to these facts. 

The region of country which we are contemplating, and through 
which the present channel of the Mississippi runs, was no doubt in 
earlier times a wide and deep estuary of the Gulf of Mexico. By the 
breaking through of a spur of a mountain range the sedimentary matters 
from the upper rivers gradually filled up this basin with rich deposits, 
until now we have a plat of land about sixty miles wide and six hundred 
miles long, in a direct line, containing about 34 000 square miles. The 
floods of the river gradually raised the whole basin so that near the head 
of this ancient estuary the elevation of the land is about 300 feet above 
the sea. The surface of the land has a quite regular descent from the 
upper end of the basin to the gulf. Through these deposits the river 
winds its tortuous course in a channel about 1 150 miles long. Expe- 
rience and observation prove most conclusively that the quantity of solid 
matter which the water of the river is able to hold in suspension is 
strictly regulated by the velocity of the current. Therefore, during the 
natural process of this land formation, whenever the flood waters es- 
caped over the banks of the channel, the loss of current in the water thus 
escaping caused the sandy or heavier portions of the solid matter held in 
suspension in it to settle almost immediately on the submerged banks, 
while the argillaceous and lighter portions, which take longer to settle, 
were carried back by the feebler current to the swamps or lower lands on 
which they were deposited over a much more extensive area. These 
lighter matters now constitute the blue and other colored clay strata 
which are found in all parts and all depths of the basin. The river 
banks were thus kept constantly higher than the lands more distant from 
the stream. Before any levees were built on them they were usually 
from ten to fifteen feet higher than the lands one or two thousand yards 
distant from the river. 

The size of the flowing volume of any river constitutes, as wiU be seen 
hereafter, a very important element in determining the velocity of its 



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260 

current, and as the loss of volume over the natural banks has the effect 
of producing a more sluggish current in the main channel, a deposition 
of sediment resulted wherever this loss occurred. 

In this manner the bed of the stream, during each successive flood, 
was built up higher and higher, while the water escaping over the banks 
built them up abo. Thus the river and its banks were both gradually 
elevated above the neighboring lands until some important breach 
occurred in one or the other bank and caused the river to seek a new 
channel through or over the lower lands. Illustrations of this process 
are frequently occurring at this time in the lower part of the basin. 
Sixty miles above the mouth of the river its flood surface is now seven or 
eight feet higher than the mean level of the gulf, and through this sixty 
miles it flows to the sea between narrow banks that have been elevated by 
repeated overflows above the sea level. From time to time the river has 
broken through these narrow embankments and found a steeper and 
shorter route to the salt water. Through such new route its heavily 
laden waters bear immense quantities of sediment which is deposited in 
the gulf at the mouth of the outlet, because the current can carry it no 
further. 

About thirty-five miles above the mouth, one of these outlets known 
as ** The Jump,'* occurred about forty years ago. It has already formed 
over a hundred square miles of territory upon which rice plantations 
exist, and on which trees are growing larger than a man's body. From 
six thousand acres of this land purchased from the State of Louisiana, 
were obtained nearly all the willows used in the construction of the 
jetties. The gradual enlargement of this sub-delta has so lengthened 
the outlet and flattened the surface slope of its branching channels, that 
the current from the river through them, even in flood time, is now too 
sluggish to carry the heavy sedimentary matters of the main river by that 
route to the sea, and hence this outlet is gradually closing up. When it 
first occurred the water in it was one hundred feet deep; now it is 
scarcely four or five. 

The extensive crevasse, called "Cubits Crevasse," about three miles 
above the head of the passes, is another illustration of the foregoing 
principle, that although the river often breaks through its narrow banks 
to find a shorter passage to the sea, it is only a temporary outlet which 
the river itself commences at once to fill up by the deposition of sediment. 
At first the flow of the water into the gulf is unobstructed, but it requires 



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only one season*s flood after the crevasse has formed to make qnite a bar 
between the crevasse and the golf, thos obstructing the flow of the cur- 
rent, and causing more deposits to be made upon this new formed bar, 
which gradually encircles the crevasse on the outer side and fills up new 
banks in the distance, which, after a while, become overgrown, still 
further obstructing the flow of the current and causing still further de- 
posits ; soon after a heavier growth of bushes and trees springs up, 
islands are formed, between which are found narrow channels which 
I>erhaps for some time are navigable for smaU boats, but which are 
eventuallj closed by the frictional resistance which this sub-delta every- 
where offers to the free flow of the water, until at last nothing but a 
slight indentation of a continuous river bank is left to mark where an 
extensive crevasse occurred many years before. These marks or indenta- 
tions, hardly perceptible, are, as it were, scars or wounds which were 
inflicted upon the river, but which it set itself at work to heal the mo- 
ment they were made. 

At the Bonnet Carr^ Crevasse the same results are seen, even without 
any artificial dam across the mouth of this crevasse, the river had already 
commenced to close up the outlet and would eventually have done it 
completely even if artificial help had not been g^ven it. The same is 
true of all other outlets, unless it may be the Atchafalaya, which no 
doubt was at one time the main channel of the river, and into which the 
river would at present pour its whole volume if the conditions were 
right for it. These crevasses, cut-offs and outlets have, during the 
history of the river, facilitated the distribution of the sedimentary mat- 
ters for the benefit of agriculture. In the advanced state of the country, 
with the present condition of agriculture, and our population, it is wise 
to consider this great basin as a heritage from the river, which it is our 
duty to utilize for the good of the country. The facts, based upon 
observation and experience, show us that the proper way to utilize this 
land formerly overflowed by the river is to confine within its natural 
channel the whole volume of water ; this we can best and most easily do 
by means of levees or embankments, built along the edge of the river. 
But we will, at the same time that we prevent the overflow of the floods 
accomplish a still more necessary result, and one more extensive in its 
influence, and that is the deepening of the channel of the river, so that 
from New Orleans to Cairo there will be a channel deep enough at aU 
seasons of the year for the deepest draught boats. It has often been 



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262 

stated, but erroneously, tbat levees tend to raise the bed of the river. 
The contrary is true, for levees deepen the bed of the river and outlets 
and crevasses always raise it, not only upon the Mississippi River but 
on the Po and Rhine and other rivers of Europe. The history of levees 
and embankments effectually disprove the statement that the bed of the 
river is raised by these works. The channels deepen and the floods 
lower as a consequence of perfect and thorough leveeing, and this, as we 
will see, is an inevitable result of the laws which control the phenomena 
of sedimentary streams where they flow in channels made through their 
own deposits. These principles or laws are very clearly stated in the 
language of Captain Eads, and I give them following : 

** The term 'slope of the river * is used by engineers to indicate the 
inclination which the surface of the flood bears to the sea-leveL When 

• the dope * is referred to without qualiflcation, it means the flood line at 
the various points along the river, and is synonymous with the term 

* the fall of the river per mile.* It has no reference to the slope of the 
bottom of the river. One end of the slope is unalterably fixed by the 
Gulf of Mexico. Other points in itsline may be lowered or elevated to 
a certain extent by natural or artificial causes. 

." The force which produces the current is the/allqfthe water from a 
higher to a lower level, and the slope is an indication of the amount of 
this force. Other conditions being the same, the steeper the slope the 
more rapid will be the current. 

•*The chief element which retards the current is the friction between 
the water and the bed of the stream. This friction increases as the 
surface in contact with the water increases, and is, therefore, greatest 
where the width is greatest, and conversely it is least where the width 
of the channel is least Hence it is evident that the velocity of the 
current may not only be increased by increasing the slope, but also by 
decreasing the friction. It must be remembered that nearly all of the 
sedimentary matter transported by the water is carried in suspension, and 
that the quantity carried is in proportion to its velocity. Only a small 
quantity of it is rolled along the bottom. Hence if the current be 
checked when its waters are heavily charged with this sediment (as they 
always are in flood time), a deposition of a portion of their burden he- 
comes inevitable. No fact in connection with the river is more thor- 
oughly established than that the current in flood time cannot be checked in 
the slightest degree without earning a deposition of some part of the sediment. 



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263 

Screens of iron wire with meshes one foot square, placed across shoalis in 
the Missouri Biver, have sufficed to retard the current enough to cause 
deposits sixteen feet deep to be formed during one flood, and in this simple 
manner new banks have been developed in excessively wide parts of that 
river to deepen its channel and lower its slope. Willow screens, first 
used at the jetties at the month of the river, for the same purpose, 
raised the bottom during one flood, over a large area at the head of the 
passes where it was from twelve to sixteen feet deep, almost to the sur- 
face of the water, and 70 or 80 acres of land covered with vegetation are 
now to be seen on the eastern side of the upper end of the South Pass 
channel that has been thus formed . 

**I have named three controlling principles which are present in 
every problem presented by the characteristic phenomena of the river. 
Each one of these is very simple in itself. It is, however, absolutely 
necessary to remember each of them to fally comprehend the subject, 
and to be able to recognize the respective influence of each in creating 
these phenomena. I will briefly repeat them to more strongly impress 
their importance. The first is the force producing the current. This 
force is simply the result of the fall of the river from a higher to a 
lower level. The second is the frictional resistance of its bed. The 
third is the intimate relation between the quantity of sediment carried 
in the water and the velocity of the current. If we increase or decrease 
the current from any cause, we increase or decrease the quantity of 
sediment carried by the river. We can increase or decrease the current 
temporarily by either of two methods ; namely, by altering the slope, or 
by altering the frictional resistance. Therefore, by these two methods 
the scouring and depositing effect can be produced. If we increase the 
current during the floods we produce a greater deepening and enlarging 
of the channel through the shoals, and they are left in better condition 
during low water, and at the same time we ultimately lower the height 
of the floods. If we decrease the current we produce shoals and higher 
floods. 

** The river, from Commerce to the Gulf, between the levees, is simply 
a grand trunk into which is poured all of the sedimentary matters of 
the tributaries. This trunk must discharge as much sediment as it 
receives, or that which it does not discharge must be left in the chan- 
nel and thus injure navigation. If it discharges more than it receives, 
the excess must be taken oat of the bed of the channel, and it will 



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264 

be deepened thereby and the floods will be lowered. Hence it follows 
that by the process of deposit, or scour, the river has the ability 
to produce a current capable of carrying its sedimentary burden, 
without loss or gain, to the sea. This velocity of current we may 
call the nominal current. In seasons of great floods the normal cur- 
rent will be more rapid than when the waters are less highly charged 
with sediment. This noroial current is produced by the river itself 
as a result of these three controlling principles. Flowing over a bed 
of deposits from which it takes up additional sediment when the current 
is too rapid, it thus deepens the bed, and with it the slope, and thus the 
current declines. If it be too sluggish, deposits fall to the bottom and 
by nosing the bed it increases the slope, and as this is steepened the 
current is accelerated until the normal velocity is again attained. It 
follows, therefore, that it is not in the power of man to permanently in- 
crease its current above the normal velocity. If it be increased from 
any cause, the water will take up an additional burden from the bed of 
the river and thus enlarge and deepen its channel, and its slope will be 
thereby reduced, and with this reduction will follow a reduction of cur- 
rent and the scouring will cease as the current diminishes until the 
normal rate is attained, and then the channel will be sufficiently en- 
larged and the slope so lowered as to prevent any further scouring. 

*' The importance of the levees as a means of improving the navigation 
of the river comes wholly from the relation which the volume of a 
sedimentary stream bears to the f rictional resistance of the bed. If the 
volume be diminished, the ratio of friction to the volume will be in- 
creased ; and, conversely, if the volume be increased, the ratio of fric- 
tional resistance will be decreased. Hence, if it can be shown that a 
higher velocity of current results from the retention of the whole 
volume within the levees, it must follow that a greater amount of sedi- 
ment will be transported, and if this amount be greater than that which 
the tributaries contribute, it must be taken up out of the bed to the 
benefit of navigation, and the flood line must consequently be lowered 
to such a degree as will finally reduce the excess of current which the 
increased volume has produced, down to the normal velocity. The in- 
crease of volume which will be secured by the closure of these gaps will 
piroduce this increased current. 

<< Through these a large part of the volume of the floods now escapes, 
and this force the river is expending in its prehistoric occupation of 



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265 

land building— a prooess wholly incompatible with the occupation of 
this vast alluvial district by man. Instead of letting this worse than 
wasted force be thus employed, the plan recommended by the Commis- 
sion proposes to utilize the entire force oi the river to deepen its chan- 
nel for the safe transit of the immense products of the valley, and for 
the safe discharge of its entire volume of flood waters without interrupt- 
ing in any manner the avocations of commerce and agriculture. That it 
is entirely practicable to retain within the present levees the entire flood 
discharge of the river, if they be repaired, even without raising them 
any higher, I will now endeavor to prove. 

'* The relation which the volume bears to the frictional resistance will 
be readily understood by examining the diagram, Plate XXVU. Let 
us suppose the Mississippi River in flood to be 118 feet deep and 3000 
feet wide, and that an additional rise of 5 feet then occurs. The increase 
of friction in this case is only on the two sides of the channel which are 
in contact with this additional 5 feet of depth. This frictional or wetted 
surface on the two banks would probably not exceed an aggregate width 
of 20 feet. The water flowing in the stream before this addition was 
made to it had a frictional surface of about 3 100 feet in width. The 6 
feet additional rise increases the cross-section in such case from about 
200 000 to 215 100 square feet, or 7i per cent, while the friction will 
have been only increased about two-thirds of 1 per cent. 

'< We see, therefore, that the ratio of friction decreases with an in- 
crease of volume, and, as a natural result of this, we must have an 
increase of velocity of current, and, consequently, an increased capacity 
of discharge in the stream. But, in addition to the increase of velocity 
from the diminished friction, the Ave feet elevation materially increases 
the slope also, and thus adds another cause to increase the current. 
Carrollton is 120 miles from the Gulf ; therefore a 5-feet rise there 
increases the slope i an inch per mile. 

*'The semi-circular diagrams are intended to show how rapidly the 
frictional resistance increases if the river be divided into two or more 
channels. The large semi-circle may be supposed to represent the bed 
of the main river, its capacity being equal to that of the two smaller 
ones. The wetted surface or frictional resistance is increased by this 
subdivision 41 per cent. Hence it is simply impossible for the water to 
flow as fast in two channeLs, unless they have steeper slopes, as it would 
if it all flowed in one channel 



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266 



** Some idea of the immense increase in the capacity of the river to 
discharge its floods, as a resnlt of this reduction of friction and increase 
of slope, maj be inferred from a few facts I have tabulated from the 
exact measorements of Humphreys and Abbot during the floods of 1851 
and 1858. They are excerpted from Appendix D of their report. These 
measurements were made at two places on the river nearly 1 000 miles 
apart, and when the floods were confined within the levees. 



FIB8T — AT COLUMBUS, TWENTY MILES BELOW CAIBO. 



1858. 



June 15, 1858, height of river above low water . 
June 28, 1858 



Difference. 



I -^ 



» 



40.1 
38 



O) 



*s 



1349 400 8.19 
1156 960 7.22 



2.1 192 440' .97 



SECOND— AT COLUMBUS. 



June 15, 1858... 
July 1, 1858 

Difference 



40.1 
33.3 



6.8 



1349 400 8.19 
841 487 '5.62 



507 913 12.57 



THmn — AT CABBOLLTON, NEAB NEW OBLEANS. 



February 24, 1851 
March 17, 1851... 

Difference. 



11.8 894 491 5.04 
14.8 ! 1152 504 6.22 



3.0 258 013:1.18 



FOUBTH — AT CABBOLLTON. 



February 21, 1851 
March 8, 1851.... 

Difference. 



10.1 
14.1 



4.1 



766 497 4.41 
1068 464 5.81 



301967 1.40 



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CO 








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Digitized by VjOOQIC 



Digitized by VjOOQIC 



267 

FIFTH — AT CABBOIiLTON. 



March 19, 1851... 
August 25. 1851.. 

Differenoe . 





U.9 
8.1 


1 149 398 
572 388 


6.19 




3.38 








6.8 


577 010 


2.81 









** We see by the first table that when the river at Oolombus was 8S 
feet above low- water mark an additional rise of only 2.1 feet waa 
sufficient to increase the mean current nearly one foot per second, and 
that the discharge was one-sixth greater. The depth of river at the time 
was about 96 feet. Therefore this 16 per cent, increase of discharge waa 
attained with the addition of only one-fortieth part of its depth. 

** The second table shows that a decrease of 6.8 feet in the height of 
the river at this place resulted in a loss of more than 2 J feet per second 
in the current and a diminution of 508 000 cubic feet per second in the 
discharge. If we suppose the banks of the river to have been 90 feet 
above the bottom of the channel, this table proves that with levees only 
7 feet high upon them, they would retain a sufficiently increased volume 
to add 60 per cent, to the discharge of the river, and over 45 per cent, to 
the velocity of the current. 

"The third table shows that at CarroUton, near New Orleans, an in- 
crease of 3 feet in the height of the river added nearly 30 per cent, to 
the amount which was discharged, (almost doubling the percentage of 
increase shown with a rise of 2.1 feet at Columbus,) while the current 
was accelerated at the same time more than 20 per cent. 

" The fourth table shows that at four feet greater height of the river 
it discharged 40 per cent, more water and that its current was increased 
32 per cent. 

'* The fifth table shows that with a difference of only 6.8 feet the dis- 
charge of the river at CarroUton was more than double. The river here 
at the lowest stage was 115 feet deep. Hence there was an increase of 
only one-seventeenth part of its total depth required to produce this 
astonishing difference in the discharge of the river. The velocity was at 
the same time increased 85 per cent. 

** These tables are the result of actual observation and careful meas- 
urements. They represent stubborn facts, without any theorizing, and 
they show how absurd are some of the statements made as to the effect of 
outlets in lowering the floods of the river. For instance, the fifth table 



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268 

bIiows that when the river, (March 19, 1851,) was nearly up to the high- 
est water-mark known at Carrollton, it would have required an outlet 
larger than the Mississippi itself to lower it 6.8 feet Such outlet would 
have had to discharge 577 000 cubic feet per second, while the whole 
river could only discharge 572000 feet, when its surface was 6.8 feet 
lower. This enormous quantity of water (577 000 cubic feet per second) 
would cover a square mile one foot deep in about forty-eight seconds, in 
twenty-four hours it would cover 1 800 miles to the same depth, and in 
less than a fortnight it would put an average depth of three feet over an 
area as large as the entire State of New Jersey. To lower the river only 
two feet at Carrollton when in flood, would require an outlet as big as 
Bed River. This is because such loss of volume lowers the slope and in- 
creases the frictional resistance in the main stream below the outlet ; and 
this causes it to flow more slowly, and thus prevents that great reduc- 
tion in its height which the thoughtless would expect. 

** When we refer to the three principles governing this problem and 
know how thoroughly they are established by experience, observation 
and experiment, and remember the intimate relation existing between the 
'quantity of sediment carried and the velocity of the current, it would seem 
impossible to arrive at any other conclusion than that the loss of velocity, 
which invariably accompanies a lower height of the flood line, cannot 
fail to result in a deposition of sediment in the channel of the river, 
^here such loss of velocity occurs during a flood when the water is carry- 
ing such an enormous volume of sediment. But this fact does not rely for 
proof upon the plain deductions to be drawn from a consideration of the 
three principles we have referred to. The numerous soundings and ex- 
aminations made of the bed of the river show that below every outlet its 
channel is reduced in size by the deposits thrown down as a result of the 
loss of volume through such outlet and the consequent reduction in 
velocity of current. 

" The floods do not come so suddenly but that the increased velocity 
due to the increased volume is felt many days before the floods rise near 
the top of the levees, and if these gaps were closed I have no doubt that 
the increased velocity resulting therefrom would enable the floods to be 
discharged without any danger of their overtopping the present levees. 
It is possible that some very extraordinary flood, if it occurred the next 
year after they were closed, might break through them or escape at some 
one of the lowest points in them ; but extraordinary floods are exoep- 



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269 

tional, and it is altogether possible that before another one comes the 
channel of the river would be restored to the dimensions which it had 
when these levees were intact, and when they were capable of discharg- 
' ing any one of the ordinary floods which occurred. 

** If they be left open, new shoals and injurious changes in the chan- 
nel will be occurring at other points of the river than those selected by 
the Ck>mmission for immediate improvement, and these new obstructions 
and changes in the channel will require so much more additional work, 
and this will undoubtedly cost twice or thrice as much as it will to repair 
the levees. By repairing them the channel will not only be prevented 
from becoming worse at any point on the river, but the shoaling which 
has occurred as a result of these outlets will be removed by the e£Eect of 
the levees, and the works of improvement can then be limited to the re- 
duction of the excessively wide places which now exist, and which are 
enclosed by the present lines of levees. These wide places are the cause 
of cut-ofb, caving banks, shifting channels and vexatious shoak. 

*< The plan of improvement recommended by the Commission differs 
from any other previously proposed for the correction of the channel, 
in the fact that it looks to a rectification of the high-toaier channel, by 
the ultimate narrowing of these wide places, as the onii/ method by 
which a deep and uniform low-water channel can be permanently se- 
cured." 

Mr. Bridges advocates the outlet theory by utilizing bayous and the 
present outlets, some of which he enumerates. From the foregoing 
statements or principles that govern the flow of water, and from the 
observations made by the Commission in its examinations it is very evi- 
dent that if we apply practically, or attempt to apply, this outlet theory 
to the Mississippi River, we will certainly raise its bed and increase not 
only the extent but the frequency of its overflows, and, still further, 
will fill the channel of the river with shoals and sand bars. 

The Mississippi Biver Commission in a report dated Feb. 17, 1880, 
very clearly states why the above named results will follow the disper- 
sion of the waters of the Mississippi Biver by means of crevasses and 
other outlets. 

" It is a well established law of hydraulics that the ratio of frictional 
resistance per unit of volume increases if the sectional area be dimin- 
ished. Thus, if the volume of a river were suddenly divided by an 
island into two channels, the water flowing in them would encounter 



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270 

more frictional resistance than it met with while flowing in a single 
channel. Hence the currents through these channels would be more 
sluggish, and as the water is charg^ with sediment, the sluggish cur- 
rent would cause a deposit in the channel which would first begin at the 
upper ends, and would continue until the bottoms of the two channels 
would be so steepened, that the current would attain a velocity capable 
of carrying the suspended sediment through them without further 
deposit, and the slope of the river's surface in flood time would be 
found to be steeper through them than above and below, where the 
volume flows in a single channel. 

** In the case of a crevasse, an island is also formed having the main 
body of the river on the one side and the crevasse channel on the other 
side. As the volume flowing in the main channel below a crevasse has 
been decreased by the amount drawn o£f through it, a steeper slope in 
the main river, if the crevasse be kept permanently open, becomes 
inevitable, because the shoal below the outlet as it grows in length down 
stream, from the deposition of successive floods, gradually increases the 
frictional resistance of the volume flowing through the diminished 
channel, and this tends to check the current of th^ river above the 
crevasse, and thus the shoaling of the river bed and the raising of the 
flood line above the site of the outlet ensues as a secondary and per- 
manent effect. 

*' It is in this way that silt bearing streams flowing through alluvial 
deposits have the ability to increase or steepen their surface slopes and 
thus recover the velocity of their currents, and adjust them to the work 
of transporting the sedimentary matter with which the flood waters are 
charged, so that this matter may be carried without loss or gain. 

•*In proof of the correctness of these views, and of their full accord- 
ance with well-established hydraulic laws, we have the evidence of this 
relation between slope and volume presented in the phenomena of silt 
bearing streams aU over the world. Whenever such streams flow 
through alluvial deposits, other conditions being the same, the slope is 
least when the volume is greatest, and conversely the slope is found to 
be ** invariably increased as the volume is diminished." 

The truths above mentioned are capable of complete demonstration 
and are generally recognized by hydraulic engineers, and the effects of 
opening new outlets and enlarging present ones will result in still more 
injury to the channel, and still greater and more destructive overflows 



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271 

to the whole aUuvial region. On the other hand, there is no donbt (for 
we have facts to prove it) that a concentration of the flood waters of the 
Mississippi Eiver will decrease the flood heights, for the slope will be 
reduced by the increase of volume, as it is stated by the commission that 
''the slope is found to be invariably increased as the volume is dimin- 
isTied. 

Careful examinations show that, in the Atchafaiayoy by the increase 
of its volume (and that a very large increase), there has been a decrease 
of elevation ; but on the other hand, in the Mississippi no decrease qf 
food height has leen observed, although a large volume has been ab- 
stracted from the main river by this outlet. The gauge records at 
Natchez, Bed Eiver and Baton Bouge, show this to be a fact, although 
the abstracted volume practically amounts to the diversion of a tributary 
with about one-sixth of the flood discharge of the Mississippi Biver. 
That is to say, the Mississippi below the Atchafalaya is to-day carrying 
one-sisUh less than it did formerly , and yet no diminution in its flood line is 
observable at these points below the outlet 

No better evidence could be given than the fact that the bed of the 
main river below the Atchafalaya has gradually been filling with so 
much deposit under the influence and effects of the Atchafalaya that 
only five -sixths of the former flood volume is all that is now required to 
bring the surface of the floods to the same height on the levees that they 
attained when the main river received the volume of Bed Biver. 

Another important and deleterious effect of outlets is the raising of 
the river bed above the outlets, for in order to obtain the necessary 
increase of slope to carry a small volume in the main river, the bed of 
the river must necessarily be raised above the outlet as a secondary 
result. This theory is established by the observation of facts. 

From the foregoing statement of principles and facts, and from the 
result of studies which have been given them by experts in river 
hydraulics, it is very evident that the only practicable and proper 
method by which to permanently deepen the channel of the Mississippi 
Biver within its alluvial basin, is to concentrate the volume of its flood 
waters by confining them between embankments, and by these means to 
prevent the dispersion of the forces which alone have the power to 
abraid and deepen the river bed. This deepening also will result in a 
rectification and widening of the channel, and will give the flood waters 
room for their flow, will lower the flood slope of the river, and no doubt 



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272 

in time will (if a perfect and thorough levee system is carried out) re- 
duce the flood surface to such an extent that the overflow can be easily 
provided for, and the alluvial region saved from periodic overflows 
which have been so deleterious to the agricultural and commercial 
interests of this great district. 

The subject we have discussed is one of great importance to us as 
citizens, as well as engineers, and we should give it the study it deserves, 
for the influence of this Society upon the important questions of internal 
improvement is very great 

DisoussiON BT J. A. OcKEBSONj Membkb A. S. C. £. 

In view of the discussion brought out by the paper on the " Over- 
flow of the Mississippi," read by Mr. Lyman Bridges at the last Annual 
Convention, the following statements may be of interest The facts 
griyen are deduced from a long series of observations and surveys made 
under the direction of the Mississippi River Commission. 

It is well known that the Atchafalaya has been increasing in size for 
some time and now it carries off about one-sixth of the flood discharge 
of the Mississippi. The gauge at Natchez, however, shows that there 
has been no decrease in the flood height of the river below the outlet. 
This would seem to be conclusive proof that outlets will not afford relief 
from overflow. But there is a still more simple and obvious fact which 
can be verified during any flood by watching its progress as indicated 
by gauge readings at various points between Cairo and New Orleans. 
There can be no outlets above the mouth of the Bed Biver in conse- 
quence of the bluffs which approach the river at Memphis, Helena and 
Vicksburg. Now, even if an outlet, as the Atchafalaya, should tend to 
lower the flood line in that vicinity, there still remains the simple fact, 
that long before the flood wave reached the outlet, the entire valley 
from Cairo to the Bed Biver, a distance of 800 miles, would be sub- 
merged. It is impossible for the water to run out till the outlet is 
reached, and by that time the mischief has been done throughout the 
section lying above it 

In the discussion of the paper it was stated that "the current cannot 
be slackened in the slightest degree without depositing a part of its sedi- 
ment.** If this be true then the river must always be fully charged with 
sediment That is, it must always carry as much sediment as the 



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273 

yelodty of the current can support. An examination of the following 
table will show how |ar the above statement is true. 



DATS. 


Vklocity 
Pr. FEB 8kc. 


PABT8 IN 1 000. 


Date. 

i 


Vklocity 
Ft. per Sec. 

6.7 


SsoncEMT. 
j Pasts in 1 000. 


1879. 


3.1 


Gauge 163 


1 

Feb. 18 


Gauge 181 


Nov. 30 


48 


112 


Dec. 2 


3.2 


90 


April 9 


6.3 


' 74 


1880. 






May 4...... 


6.6 


202 


Aug. 16 


2.7 


104 


May 12 


6.2 


54 






Gauge 179 


July 10 


6.2 


1 232 


Jan. 28 


5.9 


47 






1 Gauge 185 

' ^ — _/ 


April 17. . . . 


5.7 


127 


Jan. 26 ... . 


6.3 


53 


July 8 


6.0 


207 
Gauge 181 


Feb 23 


7.3 


79 


Janl 


6.4 


184 









It will be observed 1st. That the amount of sediment carried at 
the same stage is not the same. 2d. That the most sediment is not 
necessarily carried at the highest stage. 3d. That the most sediment is 
not always carried at the highest velocity. It must be evident then that 
the river is not always fully charged with sediment The amount of 
sediment carried, must depend on the amount supplied from erosion of 
banks and other sources as well as on the amount the current is able to 
carry. 

Now inasmuch as the river is not always fully charged, the current 
may be slackened to a certain extent without reducing a deposit of its 
sediment. 

The wire screens with meshes one foot square, used in the Missouri, 
caused a deposit of sixteen feet deep. The wire itself however did not 
obstruct the current sufficiently to induce this deposit, but the meshes 
were first clogged with weeds, brush and other debris which floated 
against the screen. 



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274 ' 

Discussion bt Lyman BBmass, Member A. S. C. £. 

The subject under discussion is "The Overflow of the Mississippi 
Biver." While we agree in many particulars, with the well defined merits 
of the Concentration theories, we insist upon confining this discussion 
to the subject under consideration, namely, the Overflow of the Missis- 
sippi. 

The Dispersion theory is not applied in this case untH the maximum 
capacity of the river is reached and passed ; then a controlled overflow 
is proposed, at flood stages, of the volunle of water above the maximum 
capacity of the river, thus keeping the steady volume and regular cur- 
rent at the maximum. This certainly promises greater stability and 
more regularity in retaining the channel of the main river than is ac- 
complished by having large crevasses breaking through the levees and 
thereby, in many places, reducing the river from its maximum slope. 

In the discussion, the main question seems sometimes quite lost 
sight of, namely, what shall be done with the overflow of the Mississippi, 
over and above the maximum capacity of the river in flood stages. 

The Chief of Engineers of the United States Army recently stated 
before a committee of Congress, that at least $50 000 000 would be re- 
quired to build levees below the Bed Biver, and $50 000 000 more would 
be required above that point ; thus making necessary an expenditure of 
at least $100 000 000 before it could be hoped that the present waters of 
the Mississippi could be confined within the levees. 

We claim that the equilibrium of the sediment would not be as much 
interfered with by keeping the river at its maximum by means of con- 
trolled overflows as by the many crevasses occuring at every flood stage. 

The minority report by Captain Eads, from which so large quotations 
have been made in this discussion, was dated one month after the paper 
now under discussion was read before this Society. Many of the theo. 
ries and statements of that report are not questioned by any engineer 
but are foreign to the subject of the present discussion. It has also been 
stated that this minority report, as presented here, gives the views of 
the United States Commission, but in the first place but one signature, 
that of Captain Eads is attached to that minority report, and in the 
second place, in the discussion as presented, everything not partisan to 
the ideas of Mr. Corthell, seems to have been omitted in quoting* 
although in the report itself the views of other members of the commb- 
sion are given. 



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275 

The United States Commission, of which General Q. A. Gillmore, M. 
A. S. C. E. is Chairman, says, in its report : 

** The enlargement of the Atchafalava has steadily progressed sinoe 
the removal of the raft therefrom by the State of Lonisiana. Now it 
ha9 a capacity of discharge nearly equal to Bed Biver, and affords a line 
of least resistance for the flow of that stream to the sea. The discharge 
of Bed Biver into the Mississippi is now small and infrequent The 
outlet from the Mississippi to the Atchafalaya is almost constant, and at 
times very large. The elevation of the water surface at the junction of 
Old Biver and the Mississippi, (that is, the old mouth of the Bed Biver,) 
is almost constantly above that at the head of the Atchafalaya. The 
difference, on the 13th of last October, being 7.3 feet, in the distance of 
about five miles. There is a marked tendency to increase this differ- 
ence of level, and also to enlarge both the communication between the 
Mississippi and the Atchafalaya, and the Atchafalaya itself." 

* * We also therefore recommend that at the earliest possible time a con- 
tinous brush sill be laid across Old Biver, between Tumbull's Island and 
the Mississippi, at such point as surveys show to be advisable, with the 
object of checking the enlargement of the outlet from the Mississippi at 
that point. 

"We recommend that the study of the subject be continued, in 
order to ascertain, first the expediency of completing the divorce be- 
tween the Mississippi on the one hand and the Bed and Atchafalaya on 
the other. '* 

*' The views of the several members, however, are not in entire ac- 
cord with respect to the degree of importance which should be attached 
to the concentration of flood waters by levees as a factor in the plan of 
improvement of low- water navigation which has received the unanimous 
preference of the Commission.'' 

'*It is considered by all that levees, by confining the flood waters of 
the river within a comparatively restricted space, do tend, in some de- 
gree, to increase the scouring and deepening power of the current But 
the extent and potency of their inflaence in the improvement of the low- 
water channel, in respect to which, for the purpose of navigation merely, 
improvement is most needed, and their value, for that purpose, as com- 
pared with other methods of improvement, and as compared with their 
cost, are regarded as subjects requiring further observation and study. 



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276 ' 

and the aoctunnlfltion of farther and more comprehenflive data, before 
final conolnsions can be reached oonoeming them.'* 

In fact Mr. Gorthell and Captain Eads, show, bj the extracts qnoted 
from the minority report, that the levees maj be broken by extraordin- 
ary floods. Our proposition is to prepare for floods and exceptional 
flood stages by controlled overflows which shall retain the main river at 
its maximnm and regular velocity in times of floods and, by a system of 
sills or locks, retain the waters of its tributaries at other times. 



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AMERICAN SOCIETY OF CIVIL ENGINEERS. 

INSTITUTED 1862. 



TRA.TSrSA.0T10N"S. 

KoTK.— This Society Is not responsible as a body, for the fkcts and opinions advanced in 
any of Its publications. 



CCXL.III. 

(Vol. XI.— August, 1882.) 



HIGHWAY BRIDGES. 

By James Owen, Member A. S. 0. E. 



Pbbsbnted at the Washington Convention, May 19th, 1882. 



With Discussion by Ashbel WbijOH, President A. S. C. E. 



While it is not proposed to ofEer anTthing of a theoretical character 
in this paper, it has occurred to the writer that probably in an experi- 
ence of oyer ten years in designing and superintending the construction 
of between 400 and 500 highway bridges of all sizes, from 2 feet to 275 
feet span, costing in all about $750,000, and of all characters, there 
would be probably many points obtained by his experience of advantage 
to the profession at large and to those interested in these structures in 
particular. 

The district cared for embraces a territory of about 150 square miles, 
known as Essex County, New Jersey, with a population of about 200,000, 



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278 

divided socially into city (Newark), 130,000 ; suburban, 50,000 ; and 
rural, 20,000. 

The topographical characters embrace marsh and ordinary undulat- 
ing land on the east in the city, undulating land for the suburban, and 
a dividing ridge, somewhat precipitous, in the centre, separating the 
suburban from the rural The county is bounded on the west by the 
Passaic River, about 150 feet wide, and also on the east by the same 
river, but it is there navigable, and of a width of 300 to 400 feet The 
Morris canal also traverses the county, requiring a considerable number 
of bridges. Other than this the streams are generally small, requiring 
few bridges over 30 feet span. The total number in the whole county is 
about 1 200. The materials for construction were found in situ : good 
sandstone (Newark, Belleville), in the eastern part, trap rock in the 
centre, and an abundance of boulders in the western part, and an adjoin- 
ing market (New York) for ordinary building materials. 

Gk)od white oak also is found in the western part It will thus be 
seen that the district, furnishing all the governing circumstances, both 
physically and socially, that require different treatment in the bridge 
line, with good material and fairly liberal appropriations, gave a fair field 
for good work. 

The governing principle for the work was to erect, if possible, 
nothing of a temporary character, so as to reduce the repair account to 
a minimum, the questiqn of interest not entering as a factor of cost 

The main character of the bridges erected was as follows : 

For waterways under 4 feet : Stone box culverts ; circular brick 
sewers ; cast-iron pipes. 

From 4 to 25 feet : Brick arches ; stone walls, iron beams, planking ; 
stone walls, iron beams, brick arches and paving. 

Over 25 feet : Wrought iron trusses with iron floor girders, stringers, 
and a roadway of planking, and occasionally a roadway of brick arches 
and paving. 

Of course there are many exceptions to the above, in shape of wooden 
bridges of small and large dimensions, but nothing of a greater span 
than 50 feet 

In deciding for small spans, the following points were considered : 

If the district was very flat, or there was a liability for the culvert to fill 
up by a sudden heavy shower, ordinary box culverts were used, built of 
rubble walls and bluestone covering. These, if filled up, could be 



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279 

easily ancovered, the material removed and the oovering relaid at small 
expense. 

If there was a steady flow of water and no wash, oast-iron pipes- 
known as rejected — were very serviceable, and can be laid with a mini- 
mnm of covering. If an area wider than 24 inches were required, brick 
sewers were used, bnt unless they are deep in the ground, backing is 
required, necessitating an increase of expense, and there is also a tendency 
for the water to wash out the mortar joints in the invert before they can 
set properly, causing the bricks to become loose and pet displaced by a 
heavy freshet. The writer once constructed, for a mountain stream 
running through a village, a brick sewer 500 feet long, 6 feet in diam- 
eter, of 12 in. brickwork, without any backing, and with only 1 foot of 
oovering over top of arch. The ground it was constructed in was 
good gravel, and everything stayed in its place, great care being taken 
to ram the gravel behind and on top. In any other soil this would be 
very risky. The only trouble was the washing out of the invert joints. 
This was obviated by creating a series of small dams, and then grouting. 
By this means the necessary tightness was attained. 

Vitrified pipes are objectionable, on account of their liability to be- 
come choked, and are difficult to clean out ; also to become broken, 
and latterly have been rarely used by the writer, except for spring 
brooks deep down. Cement pipes, on account of their fickleness, 
never. 

In spans from 4 to 25 feet, where there is plenty of height between 
level of brook and highway, an arch bridge is by far the best, but, 
except in a purely agricultural region, there are objections to raising 
roads, any more than is absolutely necessary, above the normal grade of 
the ground. So fiat bridges were mostly built of stone walls, with 
either wooden beams (these rarely) and planking, iron beams and plank- 
ing, or iron beams, brick arches and paving— the latter by far the best, 
there being no necessity for repairs. 

For bridges above 25 feet, trusses of wood or iron become necessary, 
iron being the rule, and wood the exception. 

In deciding on the area for water way, the following general rules 
were adopted : 

It might be stated here that the writer found that any 
calculations for the required area based on any formula that he could 
find, were utterly inadequate in their results ; for he found that the 



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280 

action of the storms in the hilly regions was very capricious. A sudden 
heavy fall of rain in a very limited area would create a flow of watar 
that only experience could appreciate, and he was therefore compelled 
to rely on experience and the knowledge of inhabitants in the neigh- 
borhood as a guidance. 

But as the region was an old-settled country, this experience was of 
practical value, and of all the bridges built within the last ten years, 
only four have suffered seriously by freshets. 

If a new bridge were built on the site of an old one, the area was 
increased from 30 to 50 per cent, and in some cases doubled ; if on a 
new site, comparisons were made from the nearest bridges, and the 
area always increased 20 to 50 per cent., it being very necessary to 
remember that in a country increasing in population, an increased area 
of water way is required, on account of the many improvements made. 
Every house built, every street graded, causes the water to be shed much 
more quickly, and bridges should be built to the extreme, not the aver- 
age, amount of water. 

The writer has also been led to condemn the practice of dividing the 
water way of bridges less than 50 feet into a number of spans. The nec- 
essary piers are a great detriment to the flow of water, intercept brush 
and logs, causing, in some cases, a complete obstruction, and are liable 
to become undermined. The saving in the first cost is small in compari- 
son to the probable resulting expenditure afterwards. 

The following details in construction may be of service : 

Foundations, — ^For all foundations less than 4 feet in thickness, tiie 
specifications were made to require that the excavation be carried to at 
least 2 feet below level of bed of stream, and that all foundation stones 
shall be at least as long as the width of the abutment, 2 feet wide and 
1 foot thick. This is a good rule to adopt, as it admits of no dubious 
work, tf the abutments are wider than 4 feet, the stones were specified 
to be laid in this manner, which makes good work : 



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281 

If quioksand is straok, the rule is to excavate to the full width of the 
bridge, and to lay 2-inch planking longitudinally under the site of the 
abutments, and to spike to them, crossways, planking as long as the sum 
of the width of the opening, and the two abutments. This is nofc costly, 
is absolutely secure, the cross planking preventing any scouring during 
a freshet, it being 2 feet below the normal bed of the stream. This 
mode is available u^ to 25 feet span ; over that it would not be advisable 
to lay the planking all the way across, but merely underneath each 
foundation. 

In building foundations in the marshes, piles were driven, the speci- 
fication requiring a limiting penetration of | inches with a 1 200 pound 
hammer falling 20 feet Hard bottom was always reached, but the upper 
stratum being soft mud, the caps were braced across the opening, as 
there was a tendency for the mud to be forced up from under the abut- 
ments into the channel by the filling behind, which brought a cross 
strain on the tops of the piles. 

Masonwork,— There is nothing to note specially about masonwork, 
except that the writer has found it better to specify (except in small cul- 
verts) first class or coursed masonry, instead of rubble work, as he 
found he could get good coursed masonry when he couldn't get good 
rubble work, even from the same men. Of course the price was higher, 
but there were no big joints to wash or freeze out, so no repairs afterwards. 

The main points required were good stone, fuU beds and plenty of 
headers, limited to 5 feet in their distance apart on each course, thus 
obviating any veneering, the great curse ot ordinary masonry. 

-4rcA€«.— With very few exceptions, the arches (except their ends, 
which were of dressed stone) were all turned of brick, as a stone arch is 
not equal to a brick arch, unless every stone is dressed to a radius, which 
is more costly than brick, and a stone arch of ordinary flat or field stone 
(many of which exist) is a treacherous structure, and sooner or later re- 
quires renewing. 

The arches should have solid skewbacks dressed to the radius, the 
bricks laid in rowlocks keeping each course distinct ; the centre row on 
top driven snugly in a bed of mortar, and the centres struck as soon as 
the arch is turned. This allows everything to settle to an even bed. 
The practice of driving wedges of brick to key the arches, and then 
grouting, is objectionable, for where the wedges are the grouting does 
not flow, and the wedges take all the strain. 



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282 

The settlemeiit of an arch 28 feet span, 5 feet rise and 20 inches thick 
was found by the writer to be exactly I inch. In skew arches, as the 
length as a rule was much more than the span, the spiral courses were 
only laid sufficiently far from the face to give a firm rest on the shortest 
abutment ; the centre work being laid square, a butting face, not bonded, 
being made between the two. The writer has built them this way of 45° 
and 25 feet span, and they are very satisfactory. (See Plate XXVIII.) 

As almost all the bridges were over streams, the question of preserv- 
ing intact the water way became very important, so a rule was adopted 
to put a paved invert in all water ways, except where planking existed, 
for though in places the stream will remain normal or even fill up, yet 
there is an uncertainty of the former, and in the latter the paving some- 
what prevented the silting up, and when clearing by hand was found 
necessary, it preserved a limit, and gave a guide to the necessary 
digging. 

The paved inverts were laid extending 10 feet beyond each end of 
bridge, with stones 12 to 24 inches in diameter, their longest end down- 
wards, to a proper distance in gravel If the current is extremely rapid at 
times, or if the grade is steep, timber curbs 10'' x 12* were laid at each end 
of paving, with their ends properly anchored in the ground. If, as 
sometime occurs, the length is too much to properly anchor at both ends, 
insert anchor post 3 feet deep in bed of stream, and bolt the curb to 
this. Another way is to run the lower end of the paving into the bed of 
the brook at a steeper grade than that of the brook itself. In some 
cases the writer has found it necessary to build walls 6 to 10 feet high 
at end of paving, the water in a few years having eroded to that 
extent. 

Where the water way has for some reason or other been cramped, the 
paving under the bridge has been laid two feet below the general level 
of the bed of brook. This, in ordinary times, becomes silted up, but 
wlien a great rush of water occurs and the opening is filled, a head is 
created, the silt is scoured out, and the bridge acts as an inverted 
syphon, and more water way is created. Care should be taken that 
abutments are deep enough, and the bridge has sufficient dead weight to 
resist any lifting tendency of the water. This answers the purpose ad- 
mirably, and when tried has been successful. 

THmber Bridges, — As the writer has stated that but few wooden 
bridges have been built, he has but little to say on that head. 



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tc 




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283 ^ 

For spans under 20 feet the writer found it best to put in wooden 
beams, the size in proportion to span, 2 feet apart, well bridged with solid 
blocks, herring bone bridging being objectionable on account of the 
tendency it has to work loose. 

The most satisfactory arrangements at end of beams for the planking 
is as per drawing. (See Fig. 1, Plate XXIX.) 

For spans over 20 and under 30 feet ordinary A trusses were used, 
with no special feature, except that in some cases it was found necessary 
to put in white oak braces instead of a softer wood, which became rapidly 
whittled away by the unemployed inhabitants of the neighborhood. 

Mixing sand with the paint prevents, in a degree, the whittling. 

For spans of 40 to 50 feet, queen trusses were used. It is an old type, 
but seems to be the best, allowing but little vibration. The needle beama 
project for the outside braces, which consist of a 6-inch by 4-inch tim- 
ber, and a 1-inch rod, with allowance for adjustment ; on tightening this^ 
the truss was very rigid and satisfactory. 

In proportioning wooden trusses and beams, the writer made allow- 
ance for future decay. 

A very good arrangement to prevent the floor beams from decay was 
to cover the tops with ordinary tarred paper, with a lap on each side to 
let the water drip off. There are yellow pine beams covered in this way, 
put in 17 years ago, doing good service. 

In framing trusses, specifications required that all joints be coated 
with white lead before being put together, and that aU spaces between iron 
and wood be filled with the same materiaL 

Iren beams and planking, — This makes a fairly satisfactory bridge for 
the rural districts. 

^ Ordinary rolled beams were used up to 20 feet span, the sizes and 
distances apart varying as the span — the limit of 4 feet being made in the 
latter. The writer has as yet, discovered no satisfactory way of fastening 
the planking to the beams. The usual way of bolting a strip to the iron 
beams he has discarded, and inserts wooden beams, the same depth as 
the iron beams — ^masons in the ends — 8 to each plank, and spikes the 
planking to them ; he acknowledges it is cumbrous and is open to sug- 
gestion. 

The question of planking for roadway, is one of considerable import- 
ance as it is a great element in the repair item. The following is the 
practice adopted: 



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284 

Where planking, as in the rural dlBtriots, will rot out before it is 
worn out, Jersey white oak, which is an exceptionally hard, durable timber, 
is used ; in cities under the same conditions yellow pine, it being 
there less costly ; in cities where it will wear out before it rots out, 
spruce. This wood stands the wear well. The usual thickness is 3 
inches, sometimes 4, bat in all cases the following is specified: Liay no 
plank wider than 9 inches. This prevents wide joints in shrinkage. 
Bore all holes for the spikes, to prevent splitting, and put no spike 
nearer than 4 inches to the end of planking ; this necessitates a double 
row of spiking beams where joints come, but it is the best way of obviat- 
ing the nuisance of loose ends. 

Iron beams — Brick arc^.— This, in the writer's opinion, is the stand- 
ard bridge for highways, for when done it is a finished structure. 
(See Fig. 2, Plate XXIX, and also Plate XXX.) 

Rolled beams were used up to 20 feet span, beyond that plate girders 
were necessary, tied together with |-inch rods, parallel with abutments 
4 feet apart. 

Brick arches were then turned between the beams or girders, ordin- 
arily with \ rise ; where the spaces between the beams were less than 
2 feet 6 inches, 4-inch arches were put in ; beyond that, 8 inches up to 
7 feet span, the limit. The arches were then levelled with concrete and 
smoothed off with a good coat of mortar, then a water proof covering of 
tarred paper laid in a mixture of tar and asphalt, on this 2 inches of 
sand, and then the broken stone or paving blocks. 

In case where the sidewalk was higher than the roadway, the beams 
were built in a little higher, on these flagging was laid with pitched edges 
bolted down and joints leaded, the raising of the sidewalk leaves a con- 
venient opening for gutter water to flow away. (See Plate XXX.) • 

If broken stone was used, the thickness was 12 inches in centre taper- 
ing to 6. 

The beams carrying so much dead load were calculated with a factor 
of safety of 3. 

JSai/in^.— Probably no other detail has been so troublesome to handle 
as the railings for the bridges. Theoretically they would seem simple 
enough, but practically there is great difficulty in getting them per- 
manent. 

It seems to be one of the inherent traits of humanity to employ its 
idle hours sitting, if it can, on the railing of a bridge ; another tndt is, 



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LATE XXIX 

fi. SOC. CIV. ENGR'S. 

..XI.No.CCXLMI 

HIGHWAY BRIDGES. 




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285 

if the railing is of wood, to whittle it all away with praiseworthy energy, 
or if there is any give or spring to it to experimentalize as to the limit of 
the give or spring; if there is an opening large enough for a baby to 
creep through, the baby is always on hand to fulfil its seeming mission* 
None of these points are even hinted at in the text books on engineering, 
but they are potent factors in the railing question. 

In trying to overcome these difficulties the writer has adopted two 
styles of railing as standard, one of wood and one of iron, which he 
adheres to as much as he can. 

The wooden railing consists of oak, which is difficult to cut, the posts 
6 inches square, 3 rails, the top 4 inches square, the two lower 3 inches 
square, set comers upward, so as to be uncomfortable to sit on. The 
attachments are shown on the drawing. (Plate XXIX.) 

This makes a good railing for rural districts and small streams. 

The iron railing is made of wrought-iron pickets }-inch square, 6 
inches pitch, varying from 3 feet 6 inches to 5 feet high, with blunt 
points, this should be braced carefully, is neat in appearance and strong. 

All the fancy designs submitted are a snare. If of cast-iron, a small 
boy with a base ball bat soon demolishes them, and if of wrought iron, 
they generally are too frail or too expensive. 

This probably exhausts all the remarks to be made on the subject, 
except for wrought-iron truss bridges, and this branch of the work has 
been so extensively treated by so many talented engineers, it would be 
useless for the writer to say much about them, except to allude to two 
things: 

The wrought-iron highway bridge work is an extensive and increas- 
ing industry in the United States, and has practically become a 
business of itself. Workshops are now kept employed with this work 
and nothing else. To this there can be no objection, provided the busi- 
ness is carried on in a manner that shall in no way be open to criticism. 
There are hundreds of bridges built in this country of long and short 
spans, with no other assurance of strength than the guarantee of their 
builders ; if this guarantee were a professional one, nothing more could 
probably be asked, but in very many instances this is not the case. The 
company or individual who builds the bridge builds it to make money. 
Competition and inherent avidity cause a tendency to cut down ma- 
terial, and light and insecure bridges are too often the result 

The writer only alludes to this matter generally, for as far as his 



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286 

experience goes he knows but little. The rule he adopted was to draw 
up a general specification defining loads and limiting strains ; then 
only calling npon iron bridge builders of unquestionable repute to bid 
was, in his opinion, the only satisfactory way of attaining good work — 
he considering the question of life and death a serious matter, and 
with which no risk should be incurred or even the question of risk 
raised. 

The other point is one which seems, as yet, to have had but little 
attention given to it, viz., lateral and vertical vibrations. The writer 
offers no theories in the matter, but, in his opinion, all highway bridges, 
up to 75 feet, or even 100 feet span should be riveted structures, as that 
form of construction according to his observation seems best able to 
absorb or pjrevent this vibration. There are pin-connected bridges in 
his jurisdiction that have carried a 20-ton steam roller (giving a load of 
over 300 pouuds per square foot) with little deflection, which will quiver 
and vibrate to a great degree at the passage of a fast pony and carriage, 
the tension members in the trusses will so rattle that they have to be 
bound with wire, the nuts, unless the heads of pins are thoroughly 
upset, will work loose and have to be replaced, and the floor bracing 
will undulate. This condition of things seems to the writer very ob- 
jectionable, and though no defined damage takes place, it ia very prob- 
able that the molecular condition of the iron will more quickly be 
changed, and its strength deteriorated. 

To obviate this as much as possible, the writer, for the last few years, 
has given preference to riveted trusses of low depth with angle iron 
bracing and triangular panels; a structure of this kind has few flat or 
round bars to vibrate, and is to a certain extent homogeneous ; he alludes 
to this practice merely as a suggestion, and is open to correction if this 
or any of his other practices should be in any way wrong. 

In conclusion, he would allude to one fact in connection with high- 
way bridges, viz., that in the present status of the laws in the United 
States, the control of them must be vested in officers elected by the 
people or appointed, and is to an extent political. It is so in the writer's 
case, but he wishes here to have it put' on record that he was always 
seconded in his efforts to keep his bridges out of politics, always sec- 
onded in his efforts to have good work done, and always seconded in his 
efforts in erecting structures that should give a fair equivalent for the 
money spent ; more, in his opinion, cannot be asked. 



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PLATE XXX . 

TRANS. AM. SOC. CIV. E NCR'S. 

VOL.XI.No.CCXLIII. 

OWEN ON 

HIGHWAY BRIDGES. 



» S S » CCX» o*M 



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287 

There are presented herewith Plates XXVni, XXIX and XXX, 
showing a Stone Arch Skew Bridge, a Wooden Bridge, an Iron Beam and 
Briok Arch Bridge, and an Iron Beam Bridge with Brick Arches nnder 
Hoadwaj and Flagging nnder Sidewalk. 

Discussion bt Ashbel Welch, President A. S. C. E. 

In regard to the amount of water flowing away from particular storms, 
I know of an instance where a stream draining not over three square 
miles, filled, towards the end of a verj hard rain, a culvert of 170 square 
feet sectional area, and at the upper end rose two or three feet above the 
top of the arch, so that the fall through the culvert was perhaps four or 
five feet, and the velocity at the lower end sixteen or twenty feet per 
second. The basin of this stream is very hilly and the rock, often bare, 
an indurated red shale. Probably 90 per cent, of the water ran off 
within less than an hour after it fell. But this is a very extreme case. 

In a railroad bridge where was necessary to economize height, 
I suspended iron cross beams 12 feet deep below the truss, and bolted 
an oak scantling, carefully fitted, on each side, rising half an inch above 
the iron, and spiked down the rail directly on the scantling, thus : — 




So that the distance from the top of the rail to the bottom of the beam 
was 17 inches. Mr. Owen has adopted something like the same plan in 
road bridges, but has not found it necessary there to bolt the timber to 
the iron. 

When the foundation of a culvert or bridge of small span is sure to 
be always wet, I have always found it the cheapest and far the safest to 
use a timber platform, well sheet-piled, and carried some little distance 



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288 

above and below the arch or straight bridge walls. The bed timbers 
may be of flattened hemlock or other cheap timber, a foot more or less 
deep, according to span and soil, running across the opening and a little 
beyond the ontside of each abutment, covered with 2 or 3 inch plank 
according to circumstances, thus : 






kUkkkkK <.k ^^. lUk ^ vu^.0 



I never knew but one such foundation to give way, and that was very 
badly constructed, the foundation timbers not running across. On the 
contrary, I have known many bridges and culverts to give way when the 
abutments were sunken, and the span between well paved. A few years 
ago a culvert at Milford, N. J., of two semi-circular arches of 25 feet 
span, the abutments of which were sunk several feet below the pave- 
ment, and the pavement, two feet thick, was extended some 50 feet down 
stream from the lower end of the culvert, and well sheet-piled, gave way 
from undermining, first below the lower end of the pavement and then 
working up. A wooden platform would not have given away. Mr. 
Owen has gained much in safety by the wooden apron he places at the 
lower end of his pavement. 

In one case when a violent rain flood had cut a hole 8 or ten feet deep 
at the lower end of a timber foundation of a culvert of 2 arches of 25 
feet span, I sank a crib some 15 feet wide in the cavity across the whole 
width of the stream, and continued the floor of the foundation platform 
over it. The floods of 40 years since have not disturbed it. 

In a neighboring county to that in which Mr. Owen has operated, 
they formerly used pin oak extensively for bridge floors. Pin oak 
plank 2^ inches thick, seasoned very hard all through, but if 3 inches 
thick the plank did not season through, but rotted in the middle of its 
thickness, and gave out much sooner than the thinner plank. Sweet 
gum, or bilsted, as we call it in New Jersey, wears indefinitely, but does 
not stand the weather. In the old freight transhipment house at South 
Amboy is a floor which was trucked over night and day for probably a 
quarter of a century, and which shows almost no marks of wear White 
cedar, or one kind of Cyprus, wears even better. These soft, elastic, 
strong fibred woods, yield to blows or pressure but without breaking the 



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289 

fibre, and resume their original form, while most hard woods are per- 
manently indented by the same pressures or blows, and their fibres 
gradually broken. 

The Trenton Delaware Bridge built in 1804 at a cost of $180000 (a 
vast sum in those days) and which for many years was the most famous 
structure of the kind in America, was supx>orted on white pine arches 
160 feet span, 12 inches wide and about 2 feet deep. The arches were 
made up of pine plank. In 1837 I placed a railroad track on this bridge, 
adding a few inches to the depth of the arches. Where the arch was 
completely protected from the weather I found the timber perfectly sound. 
But where the rains sometimes reached it, and where the joints between 
the planks that formed the arches were not close enough entirely to 
exclude the water, nor open enough to let it entirely dry out, the out- 
sides of the arches for a thickness of 2 or 3 inches were of bony hard- 
ness, all the middle part of the wood for about half its whole thickness, 
was of the consistence of scotch snuff. The auger could be pushed 6 
inches through it without turning. Of course all such parts of the 
arches were removed. 

The question often arises whether a cheaper ' bridge that will last a 
shorter time is more economical than a more costly one that will last a 
longer time. The same question may arise respecting many other things. 

To find the comparative economy of two things of different cost and 
durability, that will answer the same purpose equally while they last, 
the following formulae will be found convenient : 

Let Che the cost and assumed real value of one of them, T the 
time it will last, a the compound interest on one dollar for that time, at 
whatever rate money is worth to the party using the thing or costs that 
party, and L the loss of the thing when done with, which may or may 
not be equal to C; let R be the real value for the purpose of the other 
thing, C its cost, T its duration, a' the compound interest for that 
time, and L' the loss on it ; and let V be the value of the thing for that 
purpose that would last forever if all circumstances remained constant. 

Then V= C +— 
a 

iJ = ,^^that is 12= (c+^^a'^ (1 + a) 
1-f-a \ a / I 

The difference between R and C is the advantage or the disadvantage 
of the thing whose cost is C\ 



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290 

Soppose a bridge that will last seven years costs 98 000, and the loss 

at the end is jnst the cost, and money costs the parties interested 7 per 

cent, what wonld be the equivalent value of a bridge that would last five 

8 000 
years, and of one that would last forever ? 8 000 + „^ = 20 900, the 

value for that place of the bridge that would last forever, and 
(.41x20900) -^ (1 + .41) = 6077, the value of one that would kst five 
years. 



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AMEEIOAN SOCIETY OF CIVIL ENGHTEEES. 

INSTITUTED 1862. 



TRA-TSTSi^CTlONS. 

NoTi.— T148 Society is not responsible, as a body, for the ikcts and opinions advanced in 
any of its publications. 



COXIilV. 

(Vol. XI.->September, 1882.) 



UNIFORMITY IN RAILWAY ROLLING STOCK. 



By O. Ohanute, Member A. S. C. E. 
Read June 21, 1882. 

Part I. — Locomotivbs and Cabs. 

Few engineers, save those whose attention has been forced to the sub- 
ject by experience, realize how much annoyance and increased cost 
result in the operating and repairing of Bailway Boiling Stock, from 
lack of uniformity in their construction, nor how much efficiency and 
economy are promoted by building them with absolutely alike and inter- 
changeable parts, so that duplicates can be kept on hand, which will be 
sure to fit, in case of breakages. 

The master mechanics of our railroads, and especially the master car 
builders, have realized the importance of the subject, and have been 
discussing it for some years, and it is with the hope of forwarding some- 
what the important reform which they are advocating, that the following 
plain relation of one experience of the Erie Bailway has been prepared. 



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292 

Until quite reoentlj, American railroad companies, in porcluusin^^ 
their engines and cars, were content to make the most broad and general 
specifications. They specified the diameter and stroke of the cylinder, 
the size of the wheels and boilers, sometimes even the weight for tiie 
locomotives ; for cars, they mentioned the dimensions of the sills and of 
the wheels, axles and journals, stated that the materials must be good, 
and the workmanship first -class ; and left the design and the details to 
the contractors and builders. 

The result was that there were about as many designs for engines and 
cars, as there were shops in the country. More, in fact, as each shop 
experimented at the expense of its patrons, and introduced whatever 
new designs it considered improvements upon its former plans. 

This was a natural and useful stage of development, for although it 
produced considerable diversity of practice, the various builders, com- 
peting in design, as well as in prices and workmanship, were constantly 
introducing improvements, and graining valuable experience. It is 
probably largely due to this competition in design that the American 
locomotive of to-day requires fewer days* work to build it and to keep it 
in repair than any other of equal power in the world. 

When, however, a railroad company desired to preserve uniformity 
in its cars and engines, it was virtually compelled to buy them all of one 
maker, and this was open to the objection that the company could never 
feel quite sure that it was obtaining the lowest comx>etitive prices, and 
also that it had sometimes to wait for many months until its favorite 
shop could fill its orders. 

Most companies were therefore often compelled by their necessities 
to buy engines and cars from several builders, and thus to introduce 
many types and designs upon their line. This had been the case with at 
least one American trunk line. 

In 1874, there were upon the line of the Erie Railway (now the New 
Tork, Lake Erie and Western Railroad) 469 locomotives. These com- 
prised no les9 than 83 different types of engines, among which were 
scattered the following numbers of different styles of parts, which, 
being peculiarly exposed to breakage, required duplicates to be kept on 
hand : 

70 different styles of cylinders. 
14 <* '* crank axles. 

17 " ** smoke-stacks. 



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293 
41 different styles of front end doors. 



25 




driving-wheel centsres. 


71 




** " boxes. 


50 




parallel rods. 


42 




driving-wheel springs. 


32 




eccentrics. 


25 




links. 



Those engineers who have had exx>erience in repairs of machinery 
will appreciate what stacks of duplicate parts, and what forests of pat- 
terns, to saj nothing of the confusion and annoyance, these figores 
represent. To those who have not snch experience, some figures .will be 
given further on which will indicate what economy even a partial reform 
has accomplished. 

In cars, the same wild diversity prevailed. In 1874 there were 11 744 
cars upon the road, comprising no less than 230 different varieties, 
among which were found the following : 

27 different styles of drawheads. 

19 " ** journal bearings. 

53 " '* journal oil boxes. 

52 ** ** brake shoes. 

Besides great divergencies in wheels, axles, trucks, framing and general 
design. 

Of bolts and nuts, and their screw-thread connections — the things of 
all others which it is important should be interchangeable — there was an 
endless variety ; but the Erie experience in this last respect was so 
peculiar and instructive that it will be treated separately in a subsequent 
part of this paper. 

In 1876, the management determined to change the gauge from the 
mistaken width of 6 feet to the standard gauge of 4 feet 8i inches, and 
to avail of that opportunity of reforming the great diversity and con- 
sequent expense in the styles of rolling stock above enumerated, by 
reducing them to a few standard types, during the process of narrowing 
them up, as well as in providing the additional equipment required by 
the change, and the consequent increase of trafSc. 

The engines were first taken in hand, and, curiously enough, investi- 
gation showed that the readiest way of diminishing the number of types 
of locomotives was to introduce a new type, that of the *' Consolidation " 



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294 

pattern, which being twioe as powerful as those of the ordinary 
''American'' pattern, then chiefly used upon the road, enabled each of 
the standard gauge "consolidation " engines to take the place of two of 
the old "American*' broad gauge engines, and largely increased the 
train loads. 

It was decided, therefore, to place a number of "Consolidation ** 
engines on the road, and in order to secure the best design, the master 
mechanic and the acting superintendent of motive power visited the 
various lines upon which such engines were working, examined the 
different patterns, and then consulted the father of Consolidation locomo- 
tives, Mr. A. Mitchell, Superintendent of the Wyoming Division of the 
Lehigh Valley Railroad, who made the first designs for such an engine 
in 1865, and succeeded in having it built, notwithstanding the adverse 
opinions of several locomotive builders, to whom the design had been 
submitted. 

This done, having gathered all the data, drawings and information 
which could be obtained, a design was next made in the draughting 
office of the chief shop of the company at Susquehanna, for a "Con- 
solidation " engine, to conform to the general Erie practice as to style of 
wheel centres, driving-boxes and bearings, rods and rod brasses, guides, 
cross-heads, taper of bolts, tender journal-boxes and bearings, and 
various other details which could be made interchangeable with those of 
other existing engines of different classes. 

This design comprises 100 sheets of large drawing paper, upon which 
are shown some 200 different drawings, with full dimensions of every 
part noted thereon, and is accompanied by a specification of 22 pages, 
describing in detail the materials to be used, the tests which they shall 
undergo, and the way in which the work is to be done. 

Having thus carefully matured a design, and described it in minute 
detail, it was expected that all the engines built under it would be 
exactly alike, and with absolutely interchangeable parts ; and in 1877 
the road began the construction of six "Consolidation" locomotives in 
its own shops, while it gave a contract for five to one firm of locomotive 
builders, and of five more to another. 

The first difficulty encountered was to maintain the integrity of the 
design. Each of the locomotive builders thought that the locomotives 
would be much better if made to cod form with iJieir practice as to details, 
and accordingly proposed some changes, those of one builder being 



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295 

different from those of the other. Some of the employees of the road 
also suggested alterations as the work progressed, which would in their 
judgment make the engines far more efficient 

The management, however, set its face like a flint against any 
changes, and in due time the locomotives were completed, placed upon 
the road, and have done excellent service ever since. 

It was thought at first that these 16 engines were quite interchange- 
able, but in a few months this illusion was dispelled by an accident. 
One of them was caught in a butting collision, had its front end stove 
in, and was towed into the shop. As it was not otherwise injured, and 
another engine of the same class, but of different builder, was standing 
in the shop, awaiting some repairs likely to detain it a few days, it was 
attempted to take off the sound front end from the engine in the shop, 
to put it on the disabled engine, and to send the latter out again that 
afternoon. 

Ton may imagine the resulting annoyance, when it was found that 
some of the bolt holes, around the periphery of the front end it was 
attempted to put on, mismatched the holes in the head of the disabled 
engine by ^ of an inch, or just enough to prevent a good fit. 

It was certain that the position and dimension of every hole had been 
carefully and accurately given on the drawings, but these failed to pro- 
vide for the ''personal equation ** in doing the work. For that differ- 
ence between men, which is such that no two mechanics are likely 
(without extraordinary care) to lay off the same distance, and especially 
a series of distances, exactly alike, even if they use the same foot rule 
and dividers, and the same method of marking reference points. 

This experience set the master mechanic at work, taking pieces off 
from one engine and trying them upon others, and while the parts were 
found generally to conform and to be interchangeable, there were differ- 
ences enough, caused by the "personal equation'* which has been 
mentioned, to prevent some of them from making a good fit, without 
chipping or filing. They came together like the cheap Yankee clocks 
which were so well abused thirty years ago, instead of fitting, as they 
should, like the pieces of a modem watch. 

Now, in ox)erating locomotives, there are certain parts which are 
particularly liable to injury, and which require considerable time to 
make anew. It is a great advantage, therefore, to be able to keep 
duplicates of those parts on hand to replace a breakage, and these 



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296 



should fit so closely as to enable the engine to resume its service at once. 
In order to provide for this, it was determined to furnish each contract- 
ing engine builder thereafter with a certain number of templates, in 
addition to the drawings and specifications, and this course has been 
followed for all the engines since put under contract, the original set of 
templates being kept in the company's own shop, and duplicates made 
as wanted. The list of these templates for a ** Consolidation " locomo- 
tive is now as follows : 

2 templates for drilling main frames. 

2 " *' laying out main frames, front end. 

template ** drilling cylinder fooe. 

*' " drilling steam-chest rest 

** ** milling out cylinder ports. 

** ** drilling cylioder-heads. 

*' ** drilling cross-heads. 

" *' drilling smoke arch-ring and front 

'' " drilling stack-base and saddle. 

** ** drilling eccentrics. 

'* *' drilling eccentric straps. 

** '* drill ng piston spider and follower. 

** ** drilling back cylinder-head for g^des. 

** '< planing back cylinder-head for guides. 

" " drilling eccentric rod. 

2 templates ** planing cylinders. 

2 " *« laying out eccentrics. 

2 *' '' turning eccentrics and straps, 

template ** drilling piston gland. 

<< ** laying out bottom of pedestals. 

*' '< laying out pedestal caps. 

'* " drilling pedestal caps. 

** ** drilling bottom front frames. 
4 gauges for size of cylinders. 

2 ** " tail pieces. 

2 ** ** cross-heads. 

1 ** ** piston-rods. 

2 *' '* main frames. 



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297 

Those templates which contain holes to be bored (and it will be noted 
that they form a majority), are provided with hardened steel bushings to 
gaide the drill in boring, and these bashed templates present a farther 
advantage, for they not only abolish the *' personal equation" and 
prevent the mechanic from making mistakes, bat they enable the builder 
to do the work with a cheaper class of workmen, and so diminish the 
cost of the locomotives. 

There are now 108 ** Consolidation " engines upon the road, and 
they are so exactly built that there is no difficulty in keeping duplicate 
parts on hand, which are sure to fit in case of accident, and thus 
bring about great savings of time and money. 

A standard passenger engine of the '* American" type of which 
some 20 have been placed upon the road, was similarly designed and 
covered by drawings, specifications and templates, and when the old 
broad gauge engines are worn out, there will probably be but 8 types of 
locomotives upon the line for the di£ferent classes of the service, instead 
of the 83 different varieties there were in 1874. 

Even among these 8 types, all the parts which it is practicable to 
make alike will be interchangeable, such as throttles, throttle levers, oil 
cups, gauge cocks, tender axles and oil boxes, brasses, &c., &c., while 
moreover the driving-wheel boxes, driving springs, eccentrics, eccentric 
straps, links, front ends, smoke-stacks, rod brasses, crank-pins, guides, 
oross-heads and similar details will be interchangeable between several 
of the types. 

Now the question will be asked, ** How does this pay ?" The best 
answer which can be given is the following table of cost of repairs for 7 
years before and 5 years since 1876, when the system was inaugurated. 



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298 

Cost op Maintenancb of Looomotivbs on New York, Lake Ebib akd 
Wbstebn Bailboad. 









Bepairs 




Year. 


No. OF 
Engines. 

440 


MiLEAOE. 






Cost. 1 

1 
$1 312 798 33 


Cost per 
100 Miles. 


1870 


9 326 379 


$14 07 


1871 


475 


10 579 766 


945 207 63 


8 93 


1872 


488 


12 318 504 


1 000 059 04 


8 11 


1873 


497 


13 697 460 


1 096 755 36 


8 00 


1874 


469 


13 123 701' 


1 064 882 73 


8 11 


1876 


461 


12 762 870 


807 719 85 


6 33 


1876 


468 


12 632 365 


890 381 03 


7 06 


1877 


466 


12 587 998 


621 543 89 


4 94 


1878 


475 


12 716 583 


646 714 97 ' 


5 09 


1879 


504 


14 174 523 


539 638 97 


3 80 


1880 


528 


14 293 876 


582 158 20 


4 07 


1881 


544 


15 905 282 


630 181 43 


3 96 



This inolades the building of new engines each year to replace those 
worn out and condemned. 

From this it will be noticed that the cost per mile mn has been re- 
duced by more than fifty per cent., and that taking into account the 
material advance in labor and materials of the past two years, it is still 
diminishing. The average cost of repairs for the five years prior to 1875, 
was 9.17 cents per mile run, while for the past 5 years it was only 4.33 
cents ; and this represents a saving of about $675 000 a year. Had the 
rate of cost of 1871 prevailed in 1881 the expenses of locomotive main- 
tenance would have been $790 492 greater than they were. 

The conclusion must not however be formed that all of the above sav- 
ings, or even a major part of them, have resulted alone from the system 
above described. Much of the economy is doubtless due to other re- 
forms introduced by the management of the road about the same time, 



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299 



as well as to the better track consequent upon the snbstitation of steel 
for iron rails, to the decrease of wages, subsequent to the panic of 1873, 
and to the fact that man j of the eng^es are new ; but a considerable part 
is certainly due to the adoption of rigid standards, and of interchange- 
able parts, and moreover a very considerable number of the old engines 
still remains, with all their imperfections, so that further benefits may be 
expected to result from the system, as it becomes extended in the future. 

The same system has been adopted for cars ; careful drawings and 
specifications have been made for a standard passenger car, a standard 
box freight car, a stock car, a platform car and a coal gondola car, and 
all new equipment added is made rigidly to conform to these standards ; 
while it is also applied to all cars rebuilt to take the place of those 
condemned, as well, so far as possible, to the old cars in the process of 
reducing their trucks to the standard gauge. 

This has wonderfully lessened the variety and amount of material 
which has to be kept on hand at the shops, to make good the wear and 
breakages, and very much expedited the performance while it lowered the 
cost of the work. 

The resulting economy in car repairs and maintenance is shown upon 
the following table of cost for several years past. 

Cost of Maintenance op Cars on N» Y., L. E. & W. R. R. 



Tkab. 

1870 

1871 

1872 

1878 

1874 

1876 

1876 

1877 , 

1878 

1879 

1880 1 

1881 1 



Number of I 

Passenger , 

And I 



346 
366 
378 
376 
344 

36H 
407 

401 
407 
396 
411 
410 



j Cost of 
I Repairs. 

: $340 216 64 
287 926 31 

273 023 16 

274 082 46 
211 768 34 

I 260 967 91 
• 383 331 91 

163 601 49 
139 048 61 
146 421 76 
182 966 24 
269 771 70 



I Number of 
Cost i)er FreiRht Cost of 

Car. I and Repairs. 

, Coal Cars. 



$966 18 
806 78 
722 28 
730 89 
616 60 

701 02 
941 85 



8840 
9 779 
10 638 
10 373 
10 775 

11274 
11337 



$778 106 12 
944 181 72 
846 193 02 
906 020 96 
920 632 82 



Cost per 
Car. 



$88 02 
96 66 
79 66 
87 84 
86 43 



I 



861 447 18 76 41 

862 274 26 ' 76 17 



383 04 


11296 


726 877 89 


' 64 26 


341 63 


11666 


624 229 39 


63 66 


367 23 


17 667 


639 491 64 


3b 40 


446 17 


20 831 


678 170 06 


32 66 


633 69 


23 309 


797 033 46 


34 19 



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300 

Prior to 1875, tUe figures are compiled from the reports to the State 
Eiigm(»er. Sabseqnent years are taken from the reports of the Auditor 
N. Y., L. E. & W. R. R. 

This is subject to the same qualifications as to the causes of the econ- 
omy, which have been mentioned as applying to the repairs of loco- 
motives, and to the further consideration that the freight equipment 
having been very largely increased during the last three years, doubled, 
in fact, the new cars are not yet sufficiently worn to require extensive 
repairs. 

It will be noted that in freight car repairs the saving has amounted to 
about 60 per cent., while in passenger car repairs it is only about 40 per 
cent., chiefiy in consequence, doubtless, of the much smaller proportion 
added. The average cost of car repairs for 5 years preceding 1875, 
was $771 42 per passenger car, and $87 19 per freight car. For the 5 
years preceding the present year, it was $434 96 per passenger, and 
$40 92 per freight car ; and these figures indicate an annual saving of 
about $136 000 for passenger, and $783 000 for freight equipment. Had 
the cost of 1871 prevailed in 1881, the expenses would have been $71 828 
greater for passenger car maintenance, and $1 453 550 greater for that of 
the freight cars. 

If even but 10 per cent, of these savings were due to the adoption of 
a rigid standard of uniformity, it would have richly repaid all the labor 
and care it has cost. 

Pabt n.— Sorbw-Thbeai>s. 

As American cars, apart from the trucks or running gear, chiefly 
consist of wood, and the various wooden parts are principally fastened 
together with bolts, the factor which becomes important in securing 
promptness and economy of repair, is that the threads upon the bolts, 
and those upon the nuts designed to go upon them, shall, for the same 
sizes, be a good fit, and absolutely uniform and interchangeable. Wood 
can be cut and fitted with ordinary tools, but a nut too small cannot be 
screwed up home, and if it be loose, it is pretty sure to rattle off. 

In contracting for all new cars and engines, therefore, the New York, 
Lake Erie and Western Railroad carefully specified that the builders 
should exclusively furnish threads of the '* United States " (or Franklin 
Institute) standard ; but at the same time, the mechanical department 
thought it well to look at home, to see how the matter stood in its own 
shops. 



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301 

In 1878, the road had nominallj adopted the " United States *' system 
and standard of screw-threads. * It had procured a number of sample 
taps and dies, and furnished a set to each shop, with instructions to 
reproduce them as required by the wearing out of the old sets. 

In 1877, or only 4 years after the adoption of this standard upon 
the Erie Bailway, it was discovered that nuts cut at some of its shops 
did not properly fit bolts of the same diameter cut at other shops. The 
matter was then throroughly inyestigated. A nut of each size was 
ordered cut at each shop, with the tap in common use, and supposed to 
be standard, and these nuts were sent to the firm of Pratt k Whitney, 
of Hartford, Connecticut, whose well known accuracy and efforts to 
maintain mechanical precision, gave assurance of thorough and correct 
results. 

In their shop the corresponding bolt thread was reproduced by 
fitting a soft plug of Babbit metal to each nut. This was screwed in 
and out, being expanded if necessary by driving a steel mandril in a 
central hole left for that purpose until it fitted perfectly, and the plugs 
so obtained were used to make measurements of the screw-threads. 
Each nut was then cut open in the centre, and the half nut of each shop 
could then be tried upon the Babbit plug representing the bolt cut at 
another shop. 

The result was surprising, and the plugs and half nuts presented a 
series of misfits which require to be seen to be appreciated. They can- 



*The "United Stetes" tyftam of torew-threads wm deTised in 18M by Mr. William 
Sellers, for the Fnuiklin Inttitate. It presents snch excellent festares thst it has been 
adopted by the U. 8. Oovemment, by the Master Mechanics' AsEOciation, the Master Oar 
Builders, and by railroad oompanies generally. Its guiding mles are as follows : 

V*, The outside diameter of the threads vary by even flraotions of inches. 

V*. The pitch, or number of threads to the inch, vary with the diameter of the bolt iB 
the following order : 

XjMrrxD States, ob Fbakxlim Inst i tut e Stakdabo. 

Diam.ofTaporDie. i A I .V i iV i Ih i \\ I J4 1 U U 

No. of Threads to Inch, ao 18 16 14 13 12 11 11 10 10 9 9 8 7 7 



Diam.ofTaporDie, 1} 1^ 1} If If 1 2| ^ 2} 8 Si 8^ 8J 4 

No. of Threads to inch. 6 65^5 6 4^4^4 4 3|8^8|3 8 

ao. The depth of the thread is made equal to 0.66 of the pitch. 

40. The angles which all the threads make with each other is 60<». 

50. The top and bottom of the threads are bounded by flat surfkoes (parallel with the body 
of the bolt), which are equal in length to 3^ of the pitch. 



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302 

not well be repreBenied on paper, bat an examination of the pieces 
reveals most serious differences.* Neither the diameters, nor the pitch, 
nor the depth of the thread, nor their angles, nor the flat surfaces were 
fonnd to agree. 

Even in the pitch, or number of threads to the inch, they do not 
agree. This was accounted for by the fact that some of the shops liad 
sent nuts cut with the tap used for engine bolts, while they had another 
tap with a different number of threads to the inch for car bolts, thong^h 
why they should differ, and how both could be the standard, is not so 
apparent 

The table on the following page exhibits the discrepancies which 
were found to exist in the two most important particulars of pitch and 
diameter, and its careful inspection is required in order to appreciate 
the diyergencies it shows. 

It will be noticed that almost all the diameters are different, and that 
not one is right. The sizes are given in 10000 of inches, and the errors 
vary from 17-10000 up to 550-10000, while every nut but one was found 
to be too large. 

The fact was that each shop, in reproducing its taps and dies, had by 
more or less imperceptible degrees, departed from the original standard* 
The diameter had been increased, the depth and angle of the thread 
had been altered, the flat surfaces at the top and bottom had been cur- 
tailed, and the threads thus given more of a Y-shape. Even where the 
right pitch had been used f it had been altered a little, and as was said 
before, and amply appears from an examination of the plugs and half 
nuts, a bolt cut at one shop was not properly fitted by a nut cut at 
another. 

Having thus found out some of its own deficiencies, the mechanical 
department next sought for what comfort it could get from those of its 
neighbors. For this purpose 22 nuts, all nominally of }-inch diameter, 
were unscrewed from as many cars belonging to 16 different railroad 
companies. The result was indeed gratifying and instructive, and is 
shown upon the list, on page 304, of the sizes which were obtained. 



* Tbeae plugs and half nuts have temporarily been deposited in the rooms of the Sodetjr 
for inspection. 

t The nnts cut with a pitch differing ftom the U. 8. Standard were Intended to lit bolta 
on old locomotives built with the arbitrary and differing systems of threads formerly pre. 
vaiUng. 



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308 






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304 



Sizes of |-ikoh Nuts. 



OwKKB OF Cab. 

Standard nut shonld be 

Lake Shore & Michigan Southern R.E.— 1, . 
«« " •• 2. . 

3.. 
New York Central A Hudson River R.R.— 1. 

2 

Flint & Pere Marquette R.R.— 1 

t( •* *♦ 2 

Lehigh Valley R.R., 1877 

Philadelphia & Reading R.R 

•Cleveland, Columbus & Cincinnati R.R.— 1 . 
<« •• •« 2. 

Erie Railway, 1876 

Michigan Central R.R 

Grand Trunk Railway— 1 

2 

Chicago & Northwestern R.R 

Toledo, Peoria & Warsaw R.R 

Chicago, Milwaukee & St Paul R.R 

Toledo, Wabash & Western R.R 

Pekin, Lincoln A Decatur R.R 

Cincinnati, Lafayette & Chicago R.R 

North Pennsylvania R.R 



No. OP 
Thbeadb 



10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 
10 



DiAMXXKB. 

0.76OO 

0.7816 

0.7637 

0.7816 

7637 

0.789O 

0.7816 

0.7637 

0.7816 

0.7637 

0.7816 

0.7816 

0.7890 

0.7816 

0.7815 

0.7815 

0.7815 

0.7816 

0.7815 

0.7815 

0.7816 

0.7816 

0.7815 



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805 

It will again be noticed from this list, that not a single nut was found 
to be of the correct diameter, although there are but three different sizes. 
A greater number of sizes could probably have been found, by examin- 
ing more cars, the aboye having been selected haphazard, but that was 
not what was being sought. 

The object was to know how the sizes ran, and it will be seen that all 
the nuts were too large, both on foreign roads and in the Erie shops, 
with the single exception of one nut from the Hornellsrille shop. 

In fact, it was ascertained that the practice was all but universal of 
cutting nuts over size, especially for car work, and that the Erie Railway 
had merely followed the general drift in departing from the standard. 

It was found that there were three reasons for this state of affairs. 

1st That the sizes of bolts on foreign cars were generally larger than 
the standard, and the Erie nuts had to be cut over size in order to fit 
them. 

2d. That, as there were several different over sizes, the nuts were cut 
loose, so as to go on the larger bolts. This resulted in bad fits and much 
shaking off of nuts. 

3d. That most of the iron delivered by the rolling mills was over size, 
and in order to avoid the expense of going over a bolt twice, in cutting 
the thread, the practice obtained of cutting all rough bolts over size. 

Indeed, so universally had these causes operated, that in 1876, only 
12 years after the making of the original standard of screw-threads, the 
makers of taps and dies systematically made them over size, and had 
even formulated a rule attempting to regulate this inaccuracy, that : 

" Up to and including f -inch diameter, the size of nuts shall be ^^4 
over the standard. Above f-inch, they shall be ;{S large." 

That is to say, a certain standard system was devised, it was nomin- 
aUy adopted by almost all the parties interested, including the railroads, 
and a rule was then straightway formulated to depart from that stand- 
iurd in one of its most important particulars. 

It was stated by the makers of taps and dies that prior to the recent 
reform in this matter, due to the efforts of the master car builders, about 
three-fourths of their sales of taps and dies consisted of those which were 
over size. 

Now, the effect of this practice was twofold, so far as car repairs were 
-concerned : 



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306 

First — The roads did nofc adhere to the same amoant of over size, as 
fnUj appears from the dimension of nuts on the Erie Railway, and on 
the several cars, a list of which has been given, and although the dififer- 
ences may be thought small, they are quite large enough either to pre- 
vent a nut from going on a bolt at all or to leave it so loose as easily to 
rattle off. 

When, therefore, a car arrived at a shop, with a nut gone, instead of 
putting on at once a standard nut, investigation had to be made as to 
the amount of over size used by the road or firm which built the car. 
If this differed from the particular inaccuracy practiced by the road do- 
ing the repairs, recourse must needs be had to the " old nut barrel,** and 
here the trouble commenced. 

*' The old nut barrel " contained the many hundred specimens of nuts 
of different sizes which had been taken off from foreign cars. They 
were picked over and tried on, one at a time, with whatever patience or 
profanity the workman might be master of, until one was found to fit. 
This fit was almost sure to be a loose one, but the nut was, nevertheless, 
screwed up, and the car sent off with a fastening tolerably certain to 
work off, and to give some other road a chance to overhaul its '* old nut 
barrel.'' If no nut was found to go on; if a bad fit could not be made 
in that way, the old bolt was knocked out and a new bolt (cut to a differ- 
ent over size) was inserted, to plague somebody else. Thus much of 
the car repairs took tenfold the time and caused tenfold the expense 
which would have been incurred if all the roads had rigidly adhered to 
the standard which they had nominally adopted, and made their screw- 
threads of exact sizes. 

The second effect of over sizes was that the roads paid for more iron 
than they ordered or required. The rolling mills all delivered iron over 
size, and upon being consulted, their managers said that they did so be- 
cause they thought that their customers preferred it. That there was 
some little additional trouble in rolling iron to exact sizes, and that it 
was safer to make it a little large, and that as they charged for actual 
weights, by the pound, there was no objection so far as they were con- 
cerned in making the bars as large as would be acceptable to the 
customers. 

Several lots of iron were then measured at the Erie shops, and they 
were found to run from ^2 ^ <i^ of ^^ ^^^ over size. The over weight 
seemed to average about 8^ per cent. Now, the Erie Railway had during the 



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307 

year 1877, cut about 700 000 pounds of round iron into bolts, and if the 
over weight be assumed at 5 per cent, (instead of 8i per cent.), it had 
probably paid for some 35 000 pounds of iron, worth, at three cents a 
pound, $1 050 more than it required. 

Moreover, it appeared by investigation, that it was costing $1 822 a 
year to maintain this bad system of inaccuracy by making the taps and 
dies in the company's own shops, and that these could be purchased for 
less money from makers who made a specialty of maintaining uniform 
accuracy. 

It then had become so clear that only annoyance, bad workmanship, 
and expense resulted from the continuance of the existing practice of 
making the taps and dies in the company's own shops, that it was de- 
termined to discontinue this and to come down to exact standard sizes as 
soon as possible. Accordingly, in October, 1878, the following order 
was issued: 

**In order to preserve uniformity in screw-threads the following 
rules shall hereafter govern : 

" 1st. All new taps, master-taps, and such dies as are not attached to 
machines, required for regular use shall hereafter be procured upon 
requisitions instead of being made at each shop as wanted. The work- 
man hitherto doing such work shall be relieved or assigi^ to other 
duties. 

*' Taps for special work may either be made or ordered, as circum- 
stances will warrant. 

"New taps and dies shall, however, be ordered only when actually 
required for use, and the present supply shall be utilized until worn 
out. 

**2d. All new engines and cars shall be constructed with screw- 
threads, bolt heads, and nuts in exact conformity with the United States 
standard known as the * Franklin Institute * or * Sellers' ' system. 

** 3d. All iron and steel received for bolts shall be carefully inspected 
to make sure that it does not run over or under size, and bars invohdng 
double cutting, or too small, shall be rejected. 

'' 4th. All new bolts, &c., for the repair of the existing rolling stock, 
shall be cut to the exact standard sizes, except in cases where great ex- 
pense or inconvenience would result therefrom. 

" 5th. Such of the existing taps and dies as may be found to differ 
from the exact standard, shall be used only to duplicate existing threads 



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308 

in repairs of the rolling stock, and only so far as necessary to prerent 
waste or extra expense.*' 

But the Erie experience did not stop here. It next obtained some 
lots of taps and dies from different makers, both those which were sup- 
posed to be of exact size and those which were made oversize, in accord- 
ance with the cnrioos role which has been mentioned . These lots were 
compared, and it was found that the taps and dies made by different 
makers did not agree as to size. 

These several makers had been saying for some time that the road 
could not hope to maintain standard sizes in its own shops. That ab- 
solute accuracy required special appliances, which these makers had 
obtained at great cost, and that it was, therefore, better to buy all taps 
and dies of them. Now, it was discovered that the product of different 
makers did not coincide, and that if the road purchased of one firm and 
wanted to preserve a standard, it could not purchase of the other. 

Next, the cause of this difference was inquired into, and the makers of 
taps and dies said that they did not know. One firm stated that it had 
spent two years in time, and over 310,000 in money, in obtaining the 
exact measurement of an inch, and its multiples and fractions, from the 
standard yard, deposited at Washington. The other firm said that they 
hadonost faithfully copied the original gauges recognized as correct, and 
made for the United States Government several years before, by a most 
careful and accurate mechanic of Massachusetts, named Fox ; and that 
there was a standard set in the Brooklyn Navy Yard, to witness their 
assertion. 

Here was at last a gleam of light. The inquiry led back to the orig- 
inal standard. The makers of these uninterchangeable taps and dies 
were accordingly told to bring down their standard gauges to the Brook- 
lyn Navy Yard, and they would all be compared together. 

This was done, and the result was apparently to make confusion 
worse confounded. The three sets of gauges did not agree with each 
other. It is true that the differences were not gpreat, being at most 
1-1000 of an inch, and such that while they could be measured by in- 
struments of precision, they cannot well be exhibited in a table ; but the 
fact remained that the gauges were not interchangeable. 

Perhaps some engineers, accustomed to measure to 1-100 of a foot, 
will say that 1-1000 of an inch is not much of a distance ; and doubtless 
in some locations it may be neglected altogether. Yet if they will 



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309 

examine the i-inch gauge and the two pings, one exactly i-inch in dia- 
meter, and the other just 1-1000 of an inch smaller, made by Pratt & 
Whitney for Mr. Forney of the Railroad Gazette, and kindly loaned by 
him ; they will find that this 1-1000 of an inch makes just the difference 
between a close fit amd a loose fit. 

It may be said farther, with respect to the comparison of the three 
sets of gauges, that those of the firm which had obtained its own measure- 
ments from the standard yard at Washington, were found to be the 
most accurate ; that next to these were the gauges of the other firm, and 
worst of all were those of the Government at the Navy Yard. This was 
accounted for by the fact, that being made of soft iron they had worn in 
nsing, and the effect of such wear, in maintaining standard size, will be 
further alluded to hereafter. The two tap and die making firms had 
been careful to case harden their gauges, and in one case they had been 
made adjustable to take up possible wear. 

Having thus traced the differences connected with the screw-threads, 
through their range of many inaccuracies, even to a difference of original 
standards of measurements, the next step was to apply a remedy. 

For this purpose a general meeting of the Master Oar Builders' Asso- 
ciation was held in New York, on the 18fch of December, 1879, to which 
were invited Mr. WiUiam Sellers, the originator of the American system 
of screw-threads, and the various manufacturers of taps and dies. 

At this meeting the existing difficulties were explained, and the qute- 
tion was fully discussed. 

It appeared that the master car builders had all encountered the 
trouble, annoyance and expense resulting from the lack of uniformity 
in screw threads, and were confident that a general reform in this re- 
spect would save hundreds of thousands of dollars annually to the rail- 
roads of the country. 

On the other hand the makers of taps and dies explained how great 
were the difficulties of maintaining, even the partial accuracy which they 
had secured, described their processes, and expressed their willingness 
to encounter further expense to secure gpreater correctness. 

Mr. Sellers, being asked for his advice, gave it at length. He de- 
scribed the methods which had been employed in the shops of William 
Sellers & Oo., to secure accuracy, and to inspect the dimensions of screw 
threads. He stated that his firm had found it more accurate and cheaper 



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310 

to buy their taps and dies than to continue their manufacture, and gave 
some very valuable hints as to the best methods to follow in future. 

In consequence of this advice it was decided by the master car build- 
ers to abandon tne use of '* over sizes *' completely in screw-threads, and 
to come down to the exact standard, as soon as possible. A committee 
was subsequently appointed, with Mr. M. N. Forney as chairman, which 
reported at the meeting just held, June 15, 1882, at which a resolution 
was adopted commending the reform to such railroads as have not yet 
carried it out. 

The makers of taps and dies, on their side, agreed to make their 
gauges agree, and to use absolutely the same standards in manufacturing 
their goods. 

The care of verifying and making these standards was entrusted to 
the firm of Pratt &. Whitney, and it has now spent two years, and a good 
deal of money, in revising its former measurements, in devising and build- 
ing, with the aid of Professor W. A. Rogers, of the Cambridge Obserra- 
tory, a new measuring machine to establish a standard inch, and in 
making accurate sets of gauges, which will be placed on the market in a 
month or two. 

The difficulties they encountered in their pursuit of the standard 
inch will be found partially described in Mr. Forney's report to the 
master car builders. 

But after the standard gauges have been made there remain two diffi- 
culties to be overcome: 

The first arises from the expansion and contraction of steel in tem- 
pering. After a screw tap has been made of soft steel, it is quite acourate, 
but before it can be used it requires hardening. In this process it be- 
comes more or less distorted, so that with all possible care the taps of 
the same makers are not absolutely uniform. This was tested on the 
Erie Railway. A dozen taps were obtained from one maker, and a nnt 
was tapped with each. They were then interchanged, and it was found 
that there were differences enough to make the taps run loose through 
some nuts and tight through others. This might be overcome by grind- 
ing the taps after hardening, but the cost would be prohibitory, and 
would be rendered nugatory by the second difficulty. 

This difficulty results from the wear of the tap or the die in actual 
use. They may be absolutely correct when put in the machine, but with 
the first nut or bolt they begin to wear, and although that wear is min- 



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311 

nielj small it becomes appreciable in time, so that a nut cut with an old 
tap will hardly go on a bolt out with an old die, and so tempt the work- 
man to resort to over sizes and bad fits. 

Impressed with these difficulties inventors have devised many inge- 
nious contrivances to overcome their results. 

It would carry us much too far to review the large family of ** nut 
locks," which have been proposed, experimented on and discarded. 
Some few are effective, but they chiefly apply to track bolts, and are be- 
yond the scope of this paper. 

It is preferred to call attention to three attempts to make the bolt and 
nut adjust themselves to each other, so as to produce a good fit, even if 
differing in original size. 

The first is an English invention, that of Mr. Ibbotson. It consists 
in boring out the outer end of the nut, and filling it with a soft metal, 
through which the bolt may thread its way, forcing the metal into a 
tight fit. 

The second is the "grip bolt" of the Harvey Manufacturing Co., of 
which a cut is given herewith. In this, the thread of the bolt is under- 




^^^>^^^^^^^^^^^M^ 




^^y^^'l/>1/l''y^^ 



cut at an acute angle, while the nut is cut with the same pitch (or pumber 
of threads per inch) but with perpendicular surfaces on the inner edge of 
the threads. The effect of this is that when the nut is screwed on, it 
" upsets " the ends of the threads on the bolt and presses them into a 
close fit, and thus prevents the tendency to loosen. 

This, however, is open to the objection that it introduces a new style 
and system of threads, and that these threads, being cut to thin edges* 
are apt to be injured. 



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312 

Mr. Harrej has, therefore, been led to inyent the third device, in 
which the Sellers system of screw-threads is retained for the bolt, bat 
the nnt is so shaped as to plow its way into a close fit 

This is effected by cutting the first half of the nnt to correspond with 
the standard thread of the bolt (making an easy fit), and by gradually 
changing the angle of the remaining threads through the second half of 
the nut, as shown upon the drawing herewith.* Thus the threads which 
are at an angle of 60 degrees with each other through the first half of the 



1234 5678 
60'' 60* 60'' 60'' 50 52^ 48 44 



BOLT £NTERS 



A 



J^<J\^^ 



J 



• Harvey Mfg. Co. Pat. Spiral Wedge or Self-fitting Nut (head section). A to B is Btraighi 
line across the tops of the threads, showing that the nut is not a tai>ered one. 

Threads numbered 1 to 4 are United States Standard, having an angle of 60°. 

From Nob. 6 to 8 the angle of the thread is constantly changing, i. e., it is growing more 
and more acute. 

To preserve the standard number of threads to the inch, the tops of the threads are 
thickened as the threads become more acute. 

These more acute threads are also deepened, giving room for the expansion of the bolt 
threads (of an angle of 60°) when this nut, with threads gradually growing more and more 
acute, is " wedged" into, or plows its way through them. 



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313 

nut, beoome at an angle of 45 degrees at the rear end of the same nut, 
the intervening portion being "a spiral wedge, which, by means of the 
starting threads upon the nnt, is made to enter the grooves of the bolt 
thready and to compress and displace the metal." The threads upon the 
rear half of the nut being grjaduallj deepened to make room for the 
flowing metaL 

The effect of screwing snch a nut on a bolt, is to pinch and squeeze 
the threads of the bolt, engaging (at a different angle) those in the rear 
half of the nut, to cause the metal to flow, and to force the bolt and nut 
to adjust themselves to each other. This undoubtedly secures tight flts, 
even when the bolts and nuts are cut to appreciably different sizes. 

Whether this system will produce in practical use the excellent results 
which it promises, whether the straining of the metal beyond the limit of 
elasticity, to cause it to flow, wiU weaken the threads, or whether the 
threads will be so distorted when the nut has to be screwed on and off a 
number of times, as to eventually result in loose fits, experience and time 
must tell. 

The object has been to point out the great economy and advantages 
which result in constructing railway rolling stock with absolutely inter- 
changeable parts ; the mechanical difficulties which stand in the way, 
and the devices which have been introduced to overcome them. It is 
hoped that these will engage the attention of this society, and that its 
members will join in promoting the reform of past inaccuracies. 



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AMERICAN SOOIETT OF CIVIL ENGINEERS. 

INSTITUTED 186 2. 



TRAlSrSA-CTIONS. 

NoTS.^Thi8 Soolety is not rMponaible, m a body, for the facts and opinions advanced in any 

of its publications. 



CCXL.V. 

(Vol. Xl.—September, 1882.) 



THE HUDSON RIVER TUNNEL. 



By WiiiiiiAM SooY Smith, Member A. S. 0. E. 
Read at the Annual Convention, May 19, 1882. 



WITH DISCUSSION 
By WiLLLAM H. Paine, Vice-President A. S. C. E. 



In order to appreciate fully the necessity and v^lue of a means of 
crossing the Hudson River from the New Jersey side to New York City, 
which shall be safe, quick, economical and uninterrupted, it is necessary 
to bear in mind the following facts and considerations : 

1st. The greatness of the traffic flowing to New York from all the 
country west and south of it, and the prospective increase of this traffic. 

2d. With but one exception, the railroads leading to New York from 
the West and South terminate on the west bank of the Hudson. 



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315 

3d. The present means of crossing by ferry is, in comparison with 
xinobstmoted passage of raiboad trains under or over the river, inconve- 
nient, slow, expensive, and at times uncertain. 

A bridge across the river is not to be thought of at any point oppo- 
site the island on which the city stands, and if one were built farther up 
the river it would be practically inaccessible to all but one of the rail- 
roads now requiring a better crossing. 

It must therefore appear that tunnels under the river a£ford the only 
available means of providing for all the railroads now built and termi- 
nating on the New Jersey shore opposite New York, and for all that may 
hereafter be built, a suitable passage for their traffic into the city. 

By a suitable passage is here meant tunnels of ample capacity, so well 
and strongly built as to command the fullest confidence of the public, 
thoroughly lighted and ventilated, and terminating in commodious sta- 
tions, conveniently located. 

The Hudson Biver, at the point at which the tunnel under it is now 
in course of construction, is one mile wide from bulkhead wall to bulk- 
head wall. 

Throughout a distance of one thousand feet from the New Jersey 
shore its depth is about ten feet at mean low tide. 

The water deepens from this point by a quite regular slope of the 
bottom through a distance of three thousand two hundred feet to the 
middle of the channel, which is sixty- two feet in depth at mean low tide. 
This depth decreases quite rapidly to twenty- five feet at the pier-head on 
the New York side, which depth is carried to within a few feet of the 
bulkhead wall. These figures are not exact, but they are sufficiently so 
to give a proper understanding of the tunnel plans, and they cannot 
be made more full and precise without going into unnecessary detail. 

The bottom consists of silt (which will be more accuratey described 
hereafter) throughout the entire width of the river. Underlying this 
silt on the New York side there is a bed of coarse sand twenty feet in 
thickness, and, below this, a stratum of coarse gravel. These strata 
being at the depth of the tunnel as planned and partly executed, the 
work on this side has to be partly executed in them. 

From a point six hundred feet out from the bulkhead wall on the 
New York side to a point sixteen hundred feet from the same, the silt is 
underlaid by rock in place at a depth of from eighty to ninety feet 
below mean low water. This rook is covered with silt, the least thick- 



Digitized by VjOOQIC 



316 

ness of which is twenty-eight feet Farther west, the borings made atr 
each one hundred feet have not penetrated through the silt, although 
they have been made, at points to a depth considerably over one hun- 
dred feet This silt is the material carried down and deposited by tha 
riyer. A sample was taken from the heading when it was 400 feet out 
from the New Jersey shore, and at a depth of sixty feet below water sur- 
face, and, after drying, analyzed by Professor Albert Leeds, of the Ste- 
vens Institute, with the foUowing result : 

Per cent. 

Combined water 5 . 13 

Combined silica 58 .95 

Free silica, or quartz 10 .32 

Protoxide of manganese 10.95 

Alumina 15 . 14 

Protoxide of iron 3.28 

Sesquioxide of iron 1 .38 

Lime 2.88 

Magnesia 1 .50 

Sodium combined as chloride . 23 

Chlorine existing in the form of chloride . 38 

Sulphuric acid Trace 

Titanic acid Trace 

These materials make up a stuff which is very finely comminuted, 
and, when containing one-third water, as it does when exposed to air 
pressure in the headings of the i tunnel, it is compact, tenacious, and 
about of the consistency of putty as used by the glaziers. In this con- 
dition it weighs 109 lbs. per cubic foot. It is almost impervious to air 
and water, and makes an excellent puddling material, though from the 
quantity of sand it contains it yields readily to a current of water, and 
behaves under its action much like quicksand. It shrinks greatly in 
drying, and where it has been exposed for a length of time to air pressure, 
the water is slowly pressed back through and out of it, and it then cracks 
and falls down. Its resistance to displacement at a depth of sixty feet below 
water surface {ten feet water and fifty feet silt) was found by experiment 
to be 5 580 pounds per square foot. Under the river and through the 
materials described the Hudson River Tunnel has been planned and is in 
course of construction. The tunnel proper extends from the foot of Fif- 



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I 

LOOSE ^ 




SAND '/;: r 



PLATE XXXI 

TRANS. AM. SOC. C!V. ENGft'S. 

VOL.Xl.No.CCXLV. 

SMITK ON 

HUDSON RIVER TUNNEL. 




SECTI 

N A 8 THR 

WEST CN D OP 



Digitized by VjOOQIC 




n L LING 




cour 



ON 
OUGH 
' CAISSON 



Digitized by 



■ 

Goyigje 



317 

teenth street, Jersey City, to the foot of Morton street, New York, and is 

5 400 feet in length ftom shaft to shaft. The bottom of the tnnnel on the 
New Jersey side is 45 feet below mean low water surface, and on the New 
York side it is 65 feet below the same. It descends with grades of from 
two to three per cent from both extremities to the deepest point under 
the channel, where, as planned, it reaches a depth of 109 feet, which it 
carries through a level section 500 feet in length. 

On the New Jersey side the work was commenced by sinking a brick 
shaft, circular in form. An attempt was then made to go out of this 
shaft with a single tunnel large enough to accommodate a double-track 
railroad. This effort failed. It was then determined to build two 
single-tracked tunnels instead of one for a double track. A temporary 
entrance was cut through the side of the shaft, and work commenced on 
the north tunnel, which was carried out between two and three hundred 
feet An effort was then made to work back and connect the tunnels 
permanently with the shaft. This effort also failed. A caisson was then 
sunk between the shaft and the end of the completed portion of the 
north tunnel. Connection was then made between the caisson and the 
north tunnel, and the south tunnel was started out of the same caisson. 
Both tunnels were afterward pushed forward several hundred feet before 
the permanent connection was made between the caisson and shaft 
This was done in November and December last. These tunnels are 
about thirty feet apart. They are nearly circular in cross-«ection, hav- 
ing a vertical diameter of 18 feet, and horizontal diameter of 16 feet, in 
the clear. They are each surrounded by a wrought-iron shell, conisting 
of plates ^'inch thick, united by inside flanges and bolts. Inside of this 
shell there is a brick lining in all the tunnel completed to about the 1st 
of last April two feet thick, but it has recently been increased to 2 feet 

6 inches, to provide for the greater pressure due to the increased depth 
reached. The south tunnel has been completed on the New Jersey side 
to a distance of 562 feet from the west side of the shaft, and the north 
tunnel is out on the same side to a distance of about 1 000 feet from the 
same point 

During the construction of bulkheads, and making connections be- 
tween caisson and shaft, and re-installation of plant on the New Jersey 
side, the rate of progress was 53 feet of single tunnel finished per month 
for eight months, through a great deal of very soft material that had 
been disturbed by the construction of docks, etc. 



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318 

Since tiiat time, during the last two months, the rate, in much better 
material, has been about 90 feet per month, <\nd it is confidently expected 
that this rate can be increased to 100 feet per month. 

The mode of construction is as follows (See Plate XXXI) : A 
wronght-iron tube called a pilot 5 feet 6 inches in diameter, consisting 
of plates i-inch thick united by interior flanges and bolts is first carried 
forward into the heading with its axis preferably about two feet above 
that of the tunnel. 

This is done by excavating a cut into the heading wide enough for 
the insertion of one of the pilot plates and deep enough to enable a 
workman to put this plate in position at the top where it is held by 
bracing from the bottom of the cut 

Another cut is then made on one side of the first one and a second 
plate of the pilot is put in place and bolted to the first pilot plate. A 
third pilot plate is put in place in the same manner on the opposite side 
of the first. Cuts are successively made and plates put in position on each 
side and brought down in the right curve to make up a complete section 
of the pilot until this first ring or section is complete. Another ring is 
then put in, in advance of this in the same way, and united by bolts to 
the one first completed. The pilot is thus advanced ring by ring until 
it is carried from 20 to 30 feet beyond the face of the heading. The 
plates of the main shell of the tunnel are then put in and connected 
with each other in the same way ; each plate of the main shell being 
braced from the pilot by radial bracing. When the excavation has been 
sufficiently advanced in this way, a 10 feet section is lined with the brick 
work; meantime the pilot and shell are carried forward without interrup- 
tion. The rear end of the pilot is braced from the finished brick-work 
and the front end is so far advanced into the material of the heading 
that it becomes fixed. The pilot thus series as a rigid centre from 
which the main shell can be conveniently held by bracing, and it serves 
as a bridge from which the unequal pressures occuring along its length 
can be held and resisted. In soft and varying material it is of manifest 
advantage. Where the character of the material is better, the pilot is 
not required and a considerable part of the tunnel has been built 
without it and probably more rapidly than it could have been done 
with it. ' 

The use of compressed air as an indispensable auxiliary in the 
construction of the Hudson tunnel marks an era in tunnel construction. 



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319 

The idea of so using it is by no means new. As long ago as 1830, an 
English patent was issued to Sir Thomas Cochrane, for this applica- 
tion of compressed air. And in his specification filed on the 20th of 
April, 1831, he fully describes the entire process now used in the con- 
struction of the Hudson River Tunnel, so far as the use of compressed 
air is concerned, including descriptions of the air-locks and bulkheads 
employed. Mr. Ghesbrough and other American Engineers gave much 
study to the same subject, years ago, and as early as 1870, the writer 
filed a caveat in the United States Patent Office for a pneumatic appar- 
atus for tunneling. A small tunnel was actuaUy constructed by the 
pneumatic process at Antwerp and finished about three years ago. 

But while these things are true and interesting as matters of history, 
it is altogether likely that D. C. Haskin, the projector of the Hudson 
Biver Tunnel and its constructor, thus far, knew nothing of them, and 
that they therefore do not detract from the credit due him as an original 
inventor. 

The manner of using compressed air as applied in the construction 
of the work under consideration, may be very briefly explained. An air- 
lock was first inserted in the wall of the shaft projecting through it and 
into the outside material. Compressed air was forced into this lock, the 
door in its advanced end was opened and the excavation of the material 
commenced. As the excavation proceeded, the air forced in aided the 
plates and bracing employed to hold the materials in position and to 
keep the water out. Without pausing to describe the accidents which 
occurred, we may simply say that the excavation has been carried for- 
ward in this way ever since. At first the whole space inside the tunnels 
was kept filled with compressed air. When they were built out so far 
that the leakage became troublesome, and the pressure needed to keep 
the water out at the deepest points too great to be safely applied to the 
roof of the tunnels in their highest parts, it became necessary to build 
air-tight bulkheads in each of the tunnels, so that the air-chambers in 
the two were independent of each other, and of the portions of the com- 
pleted tunnels in rear of the bulkheads. These bulkheads were then 
built; they are brick walls four feet thick backed by solid walls of tim- 
ber 12 inches thick and strongly braced with timber braces let into the 
brick lining of the tunnel. There are two air-locks placed in each bulk- 
head, each of which will contain all the workmen employed at any one 
time in advance of it. One of these air-locks is designed to be kept 



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320 

open toward the heading at all times, to provide a place of refage for 
the men in case of necessity. 

The movement of the materials in which the work is going on, is so 
slow, even when the air pressure is greatly reduced or entirely removed, 
that the men have ample time to avail themselves of the means pro- 
vided for their escape to the rear of the bulkheads into the completed 
parts of the tunnels. All chance of the silt or water entering these parts 
of the work, is prevented by the bulkheads, which are air-tight, and of 
course, water-tight Recently a second bulkhead with but one air-lock 
has been constructed in the north tunnel on the New Jersey side, 280 
feet in advance of the first one. 

Besides the additional safety afforded by two air-locks, the greater 
facility they afford for passing men and materials through the bulkheads 
— ^in the opinion of the writer — more than compensates for the addi- 
tional expense involved. 

The difference in density of the outer atmosphere and the compressed 
air at the heading is divided by the present arrangement in the north 
tunnel between the two chambers, one between the two bulkheads, and 
the other in advance of the second one ; so that the workmen in going 
into the heading, are not subjected to the whole change at once. 

It is claimed that this wiU reduce the injurious effects of condensed 
air at high tension, but this remains to be proven by the results. On 
the New York side a caisson has been sunk to the required depth of 
55 1^ feet below mean low water, and an opening cut through it, and 
the north tunnel commenced. The accompanying Plates XXXII and 
XXXm will show many of the details of this work. The caisson 
was sunk through made earth, piles, sand, gravel and boulders, 
with rather less than the usual hindrances, though it had to be 
very carefully done owing to the proximity of the bulkhead wall 
on one side and a 12-feet sewer on the other, and but fifteen feet 
away. The materiaLs excavated were used to load the caisson while 
sinking, and in addition to this, railroad iron and bricks were piled upon 
its deck to increase the load to the necessary amount, 2 100 net tons, in 
addition to the weight of caisson (400 tons), to overcome friction and the 
upward pressure of the compressed air in the working chamber. When 
the caisson had reached the requisite depth, an invert was put in by carry- 
ing iron plates from the sides of the caisson down in the curve desired 
for the invert ; the brick work was then laid on these plates. After the 



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321 

invert was completed, and fitted with three stand pipes connected by a 
main tmnk from which water conld be pumped in large quantity if ne- 
oessary by means of centrifugal pumps, an opening was cut through the 
side of the caisson and the north tunnel commenced. Doubts had been 
entertained by the writer and others as to the advisability of attempting 
to use the same process on the New York side which had been so suc- 
cessfully employed on the New Jersey side. The materials were known 
to be very different, and it was by no means certain that the method 
oould be made to succeed. Not that it was deemed impossible, but the 
difficulties apprehended were of such a formidable nature that attention 
was directed very naturally to other methods which seemed more prom- 
ising as to economical and practical results. It was feared that the sand 
and gravel through which the work has to be carried might not hold air 
sufficiently to keep the water out. To this it was replied that pumps could 
be employed to take care of whatever water might enter against the 
resistance offered by the compressed air. At all events, the work was 
commenced to test the matter practically before changing the plan of 
operations. When the caisson had been cut through, it was found that 
the disturbance of the surrounding materials which had taken place during 
the sinking of the caisson, had caused the silt to come down from above 
along the side of the caisson, where it formed an impervious envelope 
which aided the first operations essentially. The first plates of the main 
shell of the tunnel were put in with very little trouble. ' Indeed no extra- 
ordinary difficulty was encountered until the top plates had been carried 
out ten feet from the caisson, and the side plates several feet down from 
the top. I As the area of the face of the heading increased, the leakage of 
air so increased that an attempt was made to cover the face with an air- 
tight timber bulkhead smeared with silt. This having failed, resort was 
had to iron plates for this bulkhead, made similar to the plates of the 
shell, only plain instead of curved, and much smaller. It was found 
that the area of sand exposed, through which the air escaped, must be 
kept small, not to exceed 12 feet if possible, and that all other surfaces of 
the excvaation must be made air-tight by an impervious covering. Great 
efforts were made to dry the material by pumping, but these failed. 
Water continued to come in, bringing sand with it. [At length the air 
escaped through the sand to such an extent that the pressure left was not 
sufficient to keep the water out, and it flowed in, filling the excavation 
imd the caisson, bringing in a large quantity of sand and forcing the 



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322 

plates of the shell in on one side 16 inches. The air pressure was again 
restored, the opening stopped, and the work of putting in plates resumed. 
By proceeding very slowly, and exposing a very small surface at any 
time, the first ten feet ring of plates was at last completed, and this ring 
bricked up. The bulkhead has since been opened at the top and work 
commenced on the second ten feet ring. It is hoped that as the work 
proceeds further from the caisson the materials will be found in better 
condition, so that the work can be prosecuted more rapidly and econom- 
ically . If the covering of silt overlying the sand and gravel becomes con- 
tiuous over the work, offering no apertures through which the air forced 
into the tunnel can escape, or if the sand met with shall contain enough 
clay to make it hold air well, the extra difficulties will be much dimin- 
ished, if they do not entirely disappear, but thus far they exist as was an- 
ticipated. The writer favors the construction of the tunnel from the 
New York caisson to a point beyond the deep water channel, by means of 
caissons sunk from the surface after a system fully worked out by him in 
the year 1876, and proposed for the construction of a tunnel under the 
Detroit river, at the Oity of Detroit ; or by means of a movable caisson, 
by means of which section after section of the tunnel can be built and 
connected. If the tunnels can be carried out beyond the bulkhead wall 
by the present method, it is very desirable that they should be, as the 
sinking of caissons from the surface through this wall would be expensive, 
even if the privilege of doing so could be obtained, which is, perhaps, 
doubtfuL 

In view of the magnitude of the work, its very g^eat value when done, 
and the novelty of the processes employed in its construction, there is, per- 
haps, no more important or interesting engineering work now in progress 
than the Hudson Biver TunneL The projectors of the work have com- 
pleted so much of it abready as to fully demonstrate the practicability of 
its construction. It is only necessary, 1st, that the plan should now be 
fully matured after careful study of the work as a whole, to avoid 
difficulties which might prove very expensive if not insurmountable; 
2d, that the money needed shall be provided ; and, 8d, that the actual 
execution of the work shall be prudently, economically and energetically 
directed and controlled. 

It is a work which constantly demands the exercise of the very best 
engineering talent, supplemented by courage and skill on the part of 
the foremen and workmen, and by the good judgment and drive of the 



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328 

contractor and the pecuniary strength, plnck and liberality of the men 
who furnish the money required. With these the work can be pushed 
along steadily to completion without more than the ordinary risks and 
contingencies which attend all great subaqueous undertakings. It is 
now placed fairly in the list of legitimate enterprises, lifted out of that 
of projected or experimental undertakings, by the actual execution of a 
considerable portion of the work. And it will be so considered hence- 
forth by civil engineers who are best prepared to understand it as a work 
to be accomplished ; and by enlightened and farseeing capitftlists, who 
will appreciate its value when done. It is also time that the City of 
New York should recognize the great value of this subterranean channel 
for its business with the western and southern country tributary to it, 
and grant every privilege and facility whidh can hasten its completion. 

It will be far more valuable, less objectionable and probably no more 
costly than the entrance into the city to the Grand Central Depot on 
Fourth avenue. 

It has progressed so far already as to justify the expectation that it 
will move on to completion with no more than the ordinary hindrances 
and delays, and, when done, prove a lasting benefit to the City of New 
York, and to all the country from which it draws its great and increasing 
business. >- 

Discussion by Wm. H. Paine, ViobPbbsidbnt, A. S. C. K 

Mr. Chair7nany—1 rise to correct an impression that is abroad to thjs 
effect that whatever of success has attended this work has been achieved 
by going contrary to the advice and without the aid of engineers, which 
is not a fact. 

The credit for the accomplishment of that portion of the work that 
has been successfully done is largely due to the engineers who have been 
connected with or advised in regard to it. 

Great credit is due Mr. Haskin. The idea of using compressed air 
was original with him and the faith he had in it was not derived from 
the opinions of others. 

It is true that Lord Corcoran as early as 1830 proposed using com- 
pressed air in tunneling and devised arrangements embodying the 
principal features of Mr. Haskin's plan, going still further and intro- 
ducing a water shaft, such as was used in the East Biver Bridge caissons. 

But we do not learn that Lord Corcoran ever made any practical use 



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324 

of his ideas. And I have reason to know that Mr. Haskin had never 
heard of Lord Gorooran^s inventions prior to making his own plans. 

Great credit is also dne Mr. Haskin for the boldness, persistence and 
energy displayed in this great work. His unbounded faith in com- 
pressed air has caused him to make most thorough trial of it and has 
thereby eyolyed some most useful and practical facts both in the direc- 
tion of encouragement and warning. 

Engineers have rendered most valuable service bj indicating means 
adequate to accomplish desired ends, and by somewhat modifying the 
early announced policy of never looking ahead for, or anticipating diffi- 
culties, but meeting them fully before grappling with them. 

Had still greater dependence been placed on engineers and their 
advice been more strictly followed, some difficulties might have been 
avoided altogether or better preparation made to safely and successfully 
grapple with them. 

Mr. F. CoLUNGWOOD. — ^Do I understand the gentleman to say that 
this plan will be practical 

Mr. Wif. H. Painb. — ^I have not endorsed the plans that are now 
being carried out and that is the reason why I left the tunnel a long 
time since. 



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AMERIOAN SOCIETY OF CIVIL ENGINEERS. 

INSTITUTED 1852. 



TRiLNS^CTIOJSTS. 

NoTB.— This Society is not reeponsible, as a body, for the facts and opinions adrancsd 
in any of its publications. 



CCXLVI. 

(Vol. XI.— October, 1882.) 



PRESERVATION OF TIMBER. 



Preliminarj Report of the Committee on the Preservation of Timber, 
made to the Society at the Annual Convention, May 16th, 1882. 
The Beport is accompanied by a paper upon the Application of 
Kyanizing at Fort Ontario, New York, by William P. Jupson, 
Member Am. Soc. C. E., and by letters from J. B. Fbanois, Pftst 
President Am. Soc. C. E. ; from J. W. Hobabt, Gen. Snpt. Central 
Vermont R.B. ; from Huoh Biddlb, President, and M. Albxandbb^ 
Boad Master, Chicago, Bock Island and Pacific B. B. ; from J. W. 
Putnam, Assoc. Member Am. Soc. C. E.; and from M. G. Howb» 
Member Am. Soc. C E. 

With Discussion of the Subject by Mbndes Cohen, A. GkyiTLiEB, T. 
EoLESTON, J. B. Fbanois, C. Hebsohbl, Members Am. Soc. C. E.» 
and E. B. Andrews, Assoc. Member Am. Soc. C. E. 



PBELIMINABY BEPOBT 

Of the Committee on ''Preservation of Timber," made to the Society 
at the Annual Convention, May 16th, 1882. 

Your Committee on the Preservation of Timber is enabled to report 
good progress, but not at this time to make a final report. 



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826 

It has already gathered a large mass of information concerning past 
experience (chiefly failares) in this conntry, bnt it finds snch smons dis- 
crepancies concerning the resnlts of apparently the same processes, that 
it requires more time to complement the data that have been gathered. 

The unpleasant revelations of the last census (1880) concerning the 
proximate extinction of many of the forests which bave hitherto been so 
bountifully productive, make it apparent that the time cannot be far dis- 
tant when our people will have to stop the waste of timber which has 
been going on, and resort, for many purposes, to the artificial preserva- 
tion of wood against decay. 

Several such methods have proved successful in Europe, and are there 
generally used. In this country failure has been the rule, even where 
the same processes were nominally adopted. One of the principal prob- 
lems, therefore, which your Committee had to solve, was to account for 
this divergency of experience, so as to ascertain, if possible, the causes 
of past failures, the defects of the various processes, and the conditions 
which must be observed to ensure success. 

In order to base its report upon ascertained facts, your Committee 
determined to gatiier, as fully as practicable, the results of past experi- 
ence in this country in the preservation of wood, and to enter into com- 
munication with all those persons who might be ascertained to possess 
information on the subject. 

With this in view the Committee issued the following circular : 



Ambbjgan Society Civil Enoinbebs, ) 

127 East 23d Street, V 

New York, January 23d, 1882. ) 

8iB, — Appreciating that the rapid destruction of timber in this country 
gives increasing importance to its artificial preparation against decay, 
the American Society of Civil Engineers has appointed a Committee to 
report upon ''The preservation of timber." 

It is said that while success has been accomplished abroad, failure or 
partial failure has, until recently, been the rule in the United States, so 
that consumers of timber are generally distrustful of all methods for pre- 
serving it. 

The Committee, therefore, first desires to obtain information concern- 
ing past experience (and especially concerning failures) in this country, 



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387 

in order to ascertain whether the failure, or the snooess, was due to the 
preserving agent selected, to the quantity injected, or to the method of 
applying it. 

It issnes this circular to find out where this information can be 
obtained. 

Will you be kind enough to answer upon the enclosed postal card, 
the following questions ? 

1st. — Do you know about, or can you ascertain the result of past ex- 
periments in preserving wood in this country ? 

Answer 

2d. — If 80, where and when were they made ? 

Answer 



3d. — Kindly give us the name and address of persons who can furnish 
further information on this subject. 

Answer 



While the Committee wishes to intrude as little as possible upon the 
time of busy men, even on a subject of such general importance, it will 
gladly receive all the information and documents you may choose to send 
in this connection. 

Please address all communications to O. Ohanute, Chairman, Box 
839, New York City. 

Please keep this Circular and Card in a conspiouous place until you have 
answered it. 

With this was enclosed a postal card, addressed to the chairman, con- 
taining the three printed questions and space for their answer. 

About 1000 of these circulars have, up to the present time, been sent 
out, addressed to civil engineers, railroad superintendents, timber 
dealers and chemists. 



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328 



Thus far 151 of these postal cards have been returned, 90 of them 
containing valuable information, and giving the addresses of other parties 
who are familiar with experiments. 

To these various parties 160 letters have been written, representiDg 
correspondence with 95 different persons, asking for the particulars of 
their experience, and containing upon the form of letter sheet used the 
following foot-note, directing attention to the kind of information par- 
ticularly wanted ; 

** Note. —The 'Committee on the Preservation of Timber,' earnestly 
" solicits information concerning past experience in the impregnation 
'* and preservation of timber in this country, more particularly that oon- 
" ceming failures. 

** Parties wiU give the description of processes and results in their 
** own way, but they are requested to bear the following points in mind, 
'* in order to assist the Committee in reaching general conclusions : Ist. 
" Kinds and dimensions of timber operated on. 2d. Its condition, green 
** or dry. 3d. Its preparation for injection. 4th. Preserving ingredient 
" injected. 5th. Its quantity per cubic foot, or per tie. 6th. Method 
'' of injection. 7th. Time occupied. 8th. Subsequent use and exposure 
** of timber, (bridges, buildings, track). 9th. Results as to duration. 
'* 10th. Comparison with life of unprepared timber. 11 tb. Effect on the 
" strength and hardness of the prepared timber. 12th. Tour general 
"conclusions." 

This correspondence, together with some 30 pamphlets which have 
been gathered by the committee, and personal interviews with whatever 
parties were accessible, have furnished more or less information concern- 
ing 88 experiments, representing some 33 different processes, of which 
the following is a list : 

Experiments in America. 



Locality. 


Date. 


Pbockss. 


Maixrial. 


Ft. Ontario, Oswego, N. Y... . 


1839 


Kyan 


Timber. 


Lowell Canal Co., Mass 


1848 


t4 


II 


Syracuse & Utioa B.H 


1849 


•• 


Ties. 


Fitohburg R.B., Moss 

Phila. & Beading B.B 

Korthem Central B.B 


1853 


Kyan 


Flooring. 
Bridges. 
Ties. 


1856 




1838 
1840 


jj 


Alexandria Aqueduct 


«« ^ 


Superstructure. 



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LOCALITT. 

Lowell Canal Co., Mass 

Vermont Central E.B 

ErieB.B 

C, B. I. & P. R.E 

Havre de Grace, P. W. & B. . 

Lehigh & Susquehanna 

Ft. Point, Cal 

Charlestown, Mass 

Wabash B.B 

Phila. A Beading 

Norfolk Navy Yard 

Flushing, L. I 

Cleveland &, Pittsburgh 

Charleston, S. C 

Taunton, Gt. Biver, Mass 

St. Clair Flats, Mich 

C, B.-L &P. B.B , 

Pittsburgh City 

Staten Island Battery 

Ft Tompkins 

Battery Hudson 

Staten Island Mortar Battery . 
*• " Battery Hudson 

" *• Mortar Battery. 

Ft. Moultrie, S. C 

Ft Sumter, S. C 

Ft. Pulaski, Ga 

Ft Moultrie, S. C 



Datb. 

1850 

1856 

1861 I 

1866 I 

1866 

1867 

1876 

1877 

1877 

1867 

1876 



Pbocess. 



Burnett. 



1870 



1865 
1868 
1868 
1872 
1871 



Thilmany (old)., 
(old).. 



Burnett 

Thilmany (new) . 

Burnett 

Thilmany (old).. 



I Material. 

Timber. 
Ties. 

Bridges, Ao. 
Ties. 
Bridge. 
Ties. 
Piles. 
Timber. 
Ties. 
(< 

Piles. 
Stringers. 
Ties. 
Piles. 



Creosote 

Seely Timber. 

Creosote 'Ties. 

Seely Paving. 

iGun Platforms. 



1873 



Bethell. 



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LOCAUTT. 



Pt. Sumter. 8. C 

N. OUflfBftttery, N. Y 

Ft. Pulaski. Ga 

Ft. Jackson, Ga 

Ft. Jefferson, Dry Tortugas 

CallowhiU, St. Br., Phila 18— 

G. C. A St F. B.R., Texas. . . 1875 

Galveston City, Texas j *• 

Bound Brook, N. J j 1876 



Datb. 



1873 



Central B.B of New Jersey . 
M. A N. O. R.R.. Chef Menteur 

Hoboken, N. J 

Delaware Bay 

Boston, Mass 

Hoboken 

New Orleans Gas Co 

Houston & Texas B.R 

Phila. & Reading R.R 

East River Bridge 

Cleveland City 

Pt. Point, Cal 

C, B. A Q. R. R., N. Bost. Br. 

Phila. & Reading R.R 

Bangor. Maine 

Phila. & Columbia R.R 

Belvedere R.R 

Blackstone Br., N. Y. A N. E. 

Flushing, L. I 

Union Pacific 



1878 



1880 



18- 



Pbocbbs. 



Bethell. 



Creosote . 



Bethell. . . 
Creosote . 
Hayford . 



Creosote . 



1873 
1870 
1868 
1854 
1872 
1840 
1850 
1854 



Hayford 

Bethell 

Carbolizing.. 
Bobbins. . . 
Coal Tar 



1872 



Lime and Salt. 
Salt 



Materiai.. 



Gun Platforms. 



Flooring. 
Piles. 
Paving. 
Ties. 



' Piles, Ao. 

Piles. 

(« 

Fence Posts. 

Piles, 

Ties and PUes. 

Ties. 

Caisson. 

Paving. 

Piles. 

Ties. 
<t 

Timber, Ao. 
Stringers. 

Bridge. 
Ties. 



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331 



LOCALITT. 



' Datb.1 



Pbooess. 



Material. 



Union Pacific ! 1868 

ErieB.R 1 1858 Boring out oentre.....| Bridges. 

C. B. A Q.E.B., Aurora. | 1870 ! ; 

Pensacola, Fla | 1874 [Thilmany (old) . 

Indiana | lOharring 

Eastern R.R I 1846 iKyanizing 

Washington 



Bridge. 



Piles. 

Fence Posts. 
Ties, &c. 



I 



Cleveland, O. 



Boston. Oolnmbos Ave. 
Chili 



1872 ,Waterbury ■ Paving Blocks. 

" Thomas I 

• ' Detwiler & Van Guilder, 

Wirt&Hurdle I 

Keystone Paving Co ... , 

Vulcanizing 1 

Samuels 

Tait *... 

Taylor's 

Thompson 4: Co 

A. B. Tripler 

Foremanizing 

Beerizing. 

U. S. Antiseptic Co. . 

Creosote 

Thilmany 

Creosote (Paul) 

Bouoherie 



1873 



1869 
1858 



Paving. 



Ties. 



The information oonQerning these yarions experiments is, however, 
qnite fragmentary and incomplete. Many of the statements contradict 
each other, and before soond conclusions can be drawn, more data mast 
be obtained, and the evidence will have to be caref oily sifted. 

The Committee, therefore, desires more time, in order to conduct the 



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332 

inquiry with that care which its importance demands ; and to investigaie 
the matter thoroughly before forming any conclusions. This it hopes to 
do during the coming year, and to report either at the annual meeting or 
the next annual convention. 

The Ck>mmittee earnestly solicits the aid of all members of the Society, 
as well as that of any person possessing information on the subject It 
will be particularly grateful for old pamphlets and reports on wood 
preservation, and will give due credit to those who may furnish infor- 
mation. 

Meanwhile, in order to give the Society an idea of the kind of infor- 
mation which it is possible to obtain, the Committee begs to submit the 
following contributions which it has received, concerning three of the 
more successful processes now used for the preservation of timber : 

1st A valuable paper by Mr. W. P. Judson, United States Assistant 
Engineer, Member of the Society, upon the application of Eyanizing at 
Fort Ontario, New York. 

2d. A letter from Mr. J. B. Francis, Past President of the Society, 
giving an account of his experience in Kyanizing, 

3d. A letter from Mr. J. W. Hobart, General Superintendent of the 
Central Vermont Bailroad, stating the experience of that road in Bur- 
nettizing. 

4th. A letter from Mr. Hugh Biddle, President of the Chicago, Bock 
Island and Pacific Bailroad, enclosing a report from Mr. M. Alexander, 
Boadmaster, concerning experiments on that line in Bumettizing and 
oreosoting. 

5th. A report from Mr. J. W. Putnam, member of this Committee, on 
creosoting on the Mobile and New Orleans Bailroad. 

6th. A letter from Mr. M. G. Howe, Member of the Society, concern- 
ing creosoting on the Houston and Texas Central Bailway. 
Bespectfully submitted, 

O. Chanutb, Chairman, New York, 

B. M. Harbod, New Orleans, 
G. BousoABEN, Cincinnati, 
E. B. Andrews, New Yorjt, 
E. W. BowDiTCH, Boston, 
Coii. G. H. Mendell, San Francisco, 

C. SHAiiEB Smith, St Louis, 
J. W. Putnam, New Orleans, 



■ Committee, 



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333 



PAPERS ACCOMPANYING THE REPORT 



COMMITTEE ON THE PRESERVATION OF TIMBER. 



Letter from J. B. Francjis, Past PREsroENT, Am. Soo. C. E. : 

O. Chanute, Esq., 

Chairman of the Gommitlee of the Am, Soc'y of Civil Engrs. 
on the Preservation of THmber, 

Dear Sir, — In reply to your circular of January 23d, last, I have to 
say : That the process for the preservation of timber from rapid decay, 
called Kyanizing, has been carried on here, under my direction, since 
1848. As conducted here, it is simply the immersion of the timber for a 
period of time, depending on its thickness, in a solution of corrosive 
sublimate, namely, one pound of corrosive sublimate in one hundred 
pounds of water ; for boards one inch in thickness, two days immersion 
is allowed, and an additional day for each additional inch in the least 
thickness. 

John Howard Kyan*s patent was taken out in England, March 31, 
1832, and it was also patented in the United States. The effect of cor- 
rosive sublimate in preventing putrefaction had long been known, and 
its application to prevent the decay of timber was favorably received. 

Professor Faraday delivered a lecture upon it before the Royal Insti- 
tution, and it was extensively used by Brunei and others, and a company 
called the Anti Dry Rot Company established works where timber, can- 
vas and cordage were Kyanized. In the United States it was used by 
several Railroad Co's. At Lowell, the need of some means of pre- 
venting the rapid decay of timber was strongly felt, it being extensively 
used in bridges over the canals and about the factories in situations 
favorable to decay, and leading to much expense and inconvenience, from 
its frequent renewal. 

In England, Kyanizing appears to have been entirely superseded by the 
process patented by John Bethell, July 11, 1838, commonly called creosot- 



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334 

ing, which consists in saturating the timber with an oil obtained by dis- 
tiUation from coal tar ; this oil contains a proportion of creosote, which 
is a powerful antiseptic, and is supposed to be the active ingredient in 
preventing decay. 

Ejanizing, first used herein 1848, was continued about two years, when 
Burnettizing was substituted, being a cheaper, more expeditious, and 
said to be an equally effective process. This was patented in England 
by Sir WUliam Burnett, July 26, 1838, and is similar to Eyanizing, ex- 
cept that the antiseptic is chloride of zinc, instead of corrosive subli- 
mate. 

Burnettizing was continued here until about 1862, when it had be- 
come apparent that it was less effective than Eyanizing, and we returned 
to that process, which is still continued. 

In 1862, 1 obtained specimens of various kinds of timber in common 
use in this neighborhood ; each specimen was originally about fifteen 
feet long and nine inches square ; it was cut into two equal lengths, and 
one part Eyanized and the other part retained in its natural state. In 
April, 1863, they were all set out in the ground as posts, the prepared 
and unprepared specimens side by side, where they have remained until 
now. If thought desirable, I can have them taken up and examined, 
and a statement prepared of the condition of each. I observe that one 
of your Committee is Mr. E. W. Bowditch, of Boston. I should be 
happy to show him, or any other member of the Oommittee, the speci- 
mens, and give him aU the information in my power on the subject. 

Perhaps, all I need say now is, that although Eyanizing does not 
completely prevent the decay of wood in exposed situations, our expe- 
rience of more than thirty years, has satisfied us, that the benefits de- 
rived from it far exceed the cost of the process. 

I send you by this mail a pamphlet relating to Burnettizing, printed 
while we had full confidence in it, and I shall be happy to furnish, either 
personally or by letter, any further information in my power, relating to 
either of the processes. 

Very truly yours, 

JAMES B. FRANCia 
Lowell, Mass., 

March 18, 1882. 



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S85 

Lbtteb fbom J. W. HoBABT, EsQ., Gek. Buff. CsNTiuii Vbbmont 

Bailboad. 

St. AiiBANS, Vt., ) 
April 28fch, 1882. f 
O. Chanutb, Esq., 

127 East 23d Street, New York, N. Y. : 

Dbab Sib,— In reply to jonr favor of the 25th instant, I wonld say : 
That in 1856, this road ereoted works for the purpose of extracting sap 
from wood and of infusing chemicals for the purpose of preservation. 
It was in use some four years, but it was so much work to get through 
with such large quantities of timber as are used upon a railroad, that it 
was thought best to abandon the work ; therefore, the boiler and fixtures 
were removed and sold, and nothing more was thought of the ** Bur- 
nettizing ** process until some three years since, when an old side track 
was removed, which had not been in use for several years, and which 
was nearly covered with earth and grass, still the hemlock ties were then 
found to be nearly sound, having laid there for nearly 25 years. I did 
not keep watch of other prepared timber put in at that early time, and 
as repairs are constantly going on upon a railroad, I am unable to say 
whether there are any other similar cases upon our line or not, but there 
is no doubt that the preservation of these ties was due to the process 
above named. 

The reasons for abandoning the Bumettizing works upon this road 
would seem to be, that the officers in charge at that time lost faith in 
the theory, and as it was an experiment, they did not learn of its value 
until recently discovered in the manner referred to. There is no ques- 
tion, in my opinion, regarding the value of the process. 

Yours very truly, 

J. W. HOBABT, 

GenL Supt. 
Lbtteb fbom Huqh Biddlb, Esq., Pbesident Chioago, Book Islakd 

AND PaOIFIO BaILWAY. 

Office of the Pbesident. ) 
CmoAOO, March 24, 1882. ) 
O. Chanute, Esq., 

Chairman^ Ac. : 

Deab Sib, — ^In reference to the experiments made by this company in 

treating ties and timber with preservatives, I enclose copy of a letter 



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886 

from Mr. M. Alexander, in reply to inqairies made bj me, that gives 
his experience and views as to ties treated bj two different processes. I 
will add that Mr. Alexander has been connected with this road, as road- 
master and engineer, for 25 years or more, and his statements may be 
taken as coming from one who knows of what he speaks. I will add 
further that we have a Howe truss bridge of 8 spans of 150 feet each, 
erected in the fall of 1860 (the timbers of which were Bamettized) that 
is still in ase and in fair condition ; but we intend to rebuild this season. 

Yours truly, 

HUGH RroDLE. 



Bepobt of M. Ajlexander, Esq., Boadmastbr and Enoinebb GmcAoo, 
Book Isulsd and Pacific B*y. 

BiiUE Island, III, March 23, 1882.- 
H. BiDDLB, Esq., 

Pres't a,R. I. &P. Ry: 

Dbar Sib, — In reply to your letter of March 15, asking for dates, &c., 
regarding ties that have been subjected to different kinds of treatment 
and laid in track on the C, B. I. k P. B'y, I can only give you the 
results of two lots of ties that have been treated, one of which are Bur- 
nettized and the other creosoted. 

November, 1866, we laid in main track just west of Englewood about 
2 000 soft-wood ties, ^consisting of pine, tamarack and cedar, but the 
greater proportion of them were hemlock. These ties were all treated to 
a solution of chloride of zinc, and have sustained a very heavy traffic. 
They are laid in a fine gravel ballast, and have received just the same 
attention that ties have on other parts of the road. 

I made a careful examination of these treated hemlock ties last sum- 
mer, and found at least 75 per cent, of them still in the track, and, in 
my opinion, in such a state of preservation that they will be service- 
able for two or three years longer. Some Ave qr six of these ties were 
taken out of track and found to be sound and solid in the centre, and 
only decayed to the depth of ( to | of an inch on the surface and sides. 
The rail has not worn into these hemlock ties to any greater extent than 
would have occurred with oak, and they hold a spike fully as well as the 
oak tie. The pine and cedar ties that were Bnrnettized at the same time 



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/ 



337 

have worn ont in the 15 jears' seryioe, and have disappeared. The 
tamarack have held out abont the same as the hemlock. 

Mj experience is that untreated hemlock ties decay first in the 
centre, or heart, when the spike becomes loose, and the tie crumbles ; 
but these treated ties are sound in the centre, which shows that where 
the chloride of zinc is not washed out the wood is in a perfect state of 
preservation. 

In 1872 we laid in second track, east of Washington Heights, about 
5 000 hemlock ties that were subjected to the creosoting process. These 
ties I do not believe, were thoroughlj treated ; thej seem to be tolerably 
sound at the bottom, but are badly decayed on the surface, and the rail 
wears into them to a much greater extent than it does into those that 
were treated with chloride of zinc. There is probably not more than 
from 30 to 50 per cent, of these creosoted ties now in track, and these 
will no doubt all be taken out this seaaon. 

I find that the natural life of a hemlock tie, laid in sand or gravel 
ballast, does not exceed five years ; but if thoroughly treated with chlo- 
ride of zinc, I believe they will last at least fifteen years. The creosoting 
process, if thoroughly done, will no doubt double the service of soft 
wood ties. 

For any further information I would refer you to M. Lassig, who was 
in the employ of L. B. Boomer in 1866 and 1867, and who had charge of 
his Burnettizing works at that time, and subjected large quantities of 
bridge-timber to treatment. * 

Respectfully yours, 

(Signed) M. ALEXANDER. 



Lettek from J. W. Putnam, Assoc. Mbmbeb Am. Soo. C. E. 

New Orleans, La., April 5, 1882. 
O. Chanutb, Esq., 

Cliairman Committee on Preservation of Timber : 

Dear Sir, — I have had a longer and more continuous observation of 
the deportment of timber on the New Orleans and Mobile Railroad than 
upon any other road ; and my experience and observations and the in- 
formation gathered from the bridgemen on other roads confirms the 
results on this road. 



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338 

An outline history of the use of timber on the New Orleans and Mo- 
bile Bailroad will therefore apply to most roads in the south which haye 
used the same kinds of timber. There is, however, no record of the 
time when renewab became necessary or to what extent they were made 
or the kind of timber used in each year upon any of the structures. 

I think such records are kept by some roads, and where they have 
been continued for a sufficient term of years they would afford valuable 
data for determining the relative value of different kinds of unpreserved 
woods. 

A large amount of long-leafed yellow pine and quite a quantity of 
cypress was used in the construction of the road in the years 1869-70. 
In the year 1874, extensive renewals were required. In 1875-76, still 
more extensive renewals were demanded. 

About the first of March, 1876, the rebuilding of the structures with 
creosoted timber was commenced and carried forward as rapidly as prac- 
ticable. As it had been previously determined to rebuild entirely with 
creosoted timber, only such renewab were made after 1875 as were re- 
quired for the safety of trains. 

The decay was so rapid, especially with the horizontal timber, that in 
the last bridges rebuilt in 1879, probably not more than five per cent of 
the original pine stringers and caps remained. But some of these were 
sound and would probably have lasted two or three years longer. Some 
of the timber which had been put in to replace that which first decayed 
had become so rotten as to require renewal. 

The cypress was much better than the yellow pine, and estimating 
from recollection I think that not more than twenty-five per cent, of the 
cypress had been removed on account of decay. Black cypress is much 
the most compact, heavy and durable of any kind that I have used. 
The red comes next, while the white cypress is but little better than good 
yellow pine. For cross-ties it is not as good except in straight track, 
being too soft to hold the spikes and rails. 

I think through the Southern States, where there is a long, warm 
season favorable to fermentation and decay, yellow pine may be expected 
to last from four to ten years, and red and black cypress from ten to 
twenty for ordinary trestle bridge work where kept up free from the 
ground. There is little timber other than pine and cypress suitable for 
bridge work in this section of country. 

The bridge over Chef Menteur was the first to be rebuilt of creosoted 



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339 

timber, and this was done daring the months of March, April and Maj, 
1876. It is an iron truss with spans of 110 feet resting npon pile piers, 
each pile capped with a cast-iron socket, and the whole surmounted 
by a wrought girder pier-head upon which the truss rests. 

The stringers, cross-ties and guard-rails are of wood. 

All the wood-work of the bridge, including piles, was as thoroughly 
creosoted as practicable, having an average of nearly two gallons of 
creosote oil per cubic foot. . 

The bridges over the mouths of Pasoagoula Biver were next built in 
the months of May, June and July upon the same plan. 

During the summer of 1876, several small structures, culverts and 
water-ways were built entirely of creosoted timber and also a sheet piling 
revetment along the sides of the embankment across Lake Catharine, 
which is nearly a half mile long. 

This revetment was built of creosoted inch plank, driven double, so 
as to break joints, and bearing against a wale plank or stringer, sup- 
ported by piles on the outside. 

During the following winter the bridge across the Great Bigolets, 
nearly three-fourths of a mile long, was built. The piles in these 
structures are subject to attacks of the teredo navcdi^, especially those 
at the crossing of the Pascagoula Biver, where piles a foot and a half in 
diameter have been cut off by the teredo in a single year. The piles 
and timber are now perfectly sound, not a piece— as far as I can learn— 
having shown any indication of decay. Had the timber been put in un- 
creosoted, there is no doubt that a considerable part would have had to 
be renewed before this time. How long before decay will commence or 
how fast it will progress, remains to be seen. 

During the summer of 1877 no creosoting was done, but during the 
fall and winter following a great number of water-ways and trestles and 
the bridge over Pearl Biver were built. 

Another suspension of creosoting occurred during the yellow fever 
epidemic of 1878. The work of construction was carried on during the 
winter following, and finished during the summer of 1879, by the re- 
building of the bridge across Bay Biloxi, one and one-fourth miles long, 
and across Bay St. Louis, two miles long. 

Since then no organization for bridge work has been necessary on the 
road. 

The sandy country through which the road runs makes absolutely 



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840 

tight culverts or water-wajs necessary. These have been built of creo- 
soted timber and placed in the bank so as to allow a covering of earth of 
from one to twenty feet deep. This gives an unbroken earth-bearing for 
the cross -ties, and avoids the jump or bouncing motion so often felt in 
passing open culverts. 

Since then a wharf has been built at Ship Island, a foundation put 
under the lighthouse at Horn Island, and several pieces of work put in 
on the Mobile and Montgomery Railroad. 

Wharves have been and are being built extensively in the Bay of 
Pensacola, and railroad bridges on the Pensacola and Atlantic Bailroad. 
Several thousand creosoted piles have been and will be in the waters 
of this bay, where the teredo is very destructive to timber. 

Several piles have been taken out after one or two years, in making 
changes in wharves, but have been found free from the effects of the 
teredo navalis. 

There is a piece of creosoted blook-paving in the yard of the New Or- 
leans Oaslight Company which has been in use for nine years. The 
blocks are perfectly sound and scarcely show any wear, though subjected 
to the abrasion of all their heavy hauling, carts being used for con- 
veying coke and gas-lime, which carry from three to four thousand 
pounds. 

About ten years ago— I do not know the exact date— a lot of soft, sap 
pine cross-ties were creosoted and laid on the Galveston and Houston 
Baiboad. They are reported perfectly sound, though such timber, when 
uncreosoted, is of no comparative value for such work. 

There was also a piece of paving laid in a livery stable in Gkdveston 
about the same time, which is yet sound. 

A large number of piles were creosoted in 1875 for a bridge from 
Galveston island to the mainland, but as very little oil was used in them, 
the greater part were soon cut down by the marine animals. 

The Houston and Texas Central Bailroad are laying a great number 
of sap pine cross-ties, creosoted, and with, what appear to them to be, 
very satisfactory results, though they have not been laid long enough to 
determine their entire durability. 

I have several pieces of destructible timber — gum, white birch, beech, 
willow and elm — which were creosoted in the summer of 1876, and have 
been lying in the yard, exposed to sun and rain. They are as sound as 
when cut. 



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841 

My obseryatioDs have convinced me that creosoting is valaable in 
proportion to the amount of oil used, and where practicable, it is advis- 
able to saturate the timber, or, having thoroughlj seasoned it and 
exhausted the air, a bodj of oil should be forced in sufficient to protect 
the unimpregnated timber from the fermenting and destructive particles 
in the air. I do not think the method is known by which compact timber 
of large size can be thoroughly saturated with any antiseptic material 
It is necessary, therefore, to destroy the ferment germs already in the 
timber and prevent the entrance of others by establishing an impervious 
coating. 

The character of wood seems to be so changed by contact with creo- 
sote oil that the ferment germs find no nourishment, and though the oil 
may have become as thoroughly dried out as possible, no fermentation 
or decay will take place. No timber should be cut or framed after being 
creosoted. 

I cannot well in this article refer to the different methods of treating 
timber which have been practiced, not having the data at hand ; but if, 
as Chairman of the Committee, you could have such a compilation made 
of the various methods which have been put in actual operation, and the 
results as demonstrated by the durability in service of timber subjected 
to successive baths of different material, of timber prepared by injecting 
under pressure an antiseptic preparation either with or without seasoning 
the timber, and of methods whereby timber is supposed to be saturated 
by vapors from materials which only vaporize at a temperature far above 
that to which timber can be raised, it would be valuable for reference. 
It is not a report of the methods which have been successfully used that 
alone is wanted, but also of the methods which have been tried and 
found wanting, to guard others against making the same mistakes. 

It seems to me that works for the preservation of timber have been in 
operation in this country and Europe long enough to make such a com- 
pilation extremely valuable, but I have doubts about enough reliable 
data being gathered by correspondence for such a work. 

Yours respectfully, 

J. W. PUTNAM. 



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342 
Lbtteb from M. G. Howe, Mbmbbb Am. Soo. 0. E. 

Houston and Texas Centbal Railwat. 
Division Enoineeb Aia> Supt's Office, 
Houston, April 7th, 1882, 

To the Committee on Preservation qf THmber, 

Am. Soc of Engrs,, -AT. Y, : 



i 



Gentlemen, — In answer to yonr oommunication of March 29th, on the 
BQbject of preserving timber, I would say, that the Houston and Texas 
Central Railway Company has treated about 150,000 cross-ties, and a 
small quantity of bridge and tank-frame timber with creosote or '* dead 
oil," in the last two years. 

Sufficient time has not elapsed for the results to be ascertained on this 
special work, but enough is known of the effects of *' creosote " in pre- 
serving similar timber in this climate for a period of eight years to give 
a good guarantee of success. 

The timber used thus far for ties is the short leaf '* Texas pine," a 
porous and perishable wood, that, untreated, will not last more than two 
years on or in the ground, or exposed to the weather. It takes the oil 
freely when partially seasoned, and when entirely dry will readily take 
more than two gallons to the cubic foot Our works consist of two 
cylinders 100 feet long, in which the timber is treated, calculated to stand 
a pressure of 150 pounds per square inch ; a superheater, and vacuum 
and pressure pumps, with suitable steam power and pipe connections, 
and cisterns for conveying and holding the oil. The process, in brief, 
is, first, application of superheated steam, then withdrawal of the con- 
densed steam and sap that may have come from the wood, and produc- 
tion of a vacuum, by means of a vacuum pump, the temperature being 
maintained at the same time by dry heat from the steam pipes, and 
finally following with the oil at a temperature of about 160 degrees, and 
with such pressure as may be necessary to produce the desired results. 

Our ties contain about 4^ cubic feet, and we propose to use about 5 
gallons of oil to the tie ; the length of time necessary to do this depends 
on the condition of dryness of the ties when treated. When quite dry, 
very little steam is needed, in fact it might be dispensed with ; 80 min- 
utes of exposure to superheated steam and the same length of time with 
an oil pressure of 20 pounds are sufficient. 



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343 

But if the timber is green, 4 hoars ose of the steam^ and 4 hours of oil 
pressure of 100 pounds per square inch, may not accomplish the same re- 
sult. In practice, the treatment is varied within above limits, according to 
the condition of the timber and ascertained results after treatment. Nat- 
ural seasoning is much the best, and it is considered that the saving in 
fuel, and cost of running the works, bj reducing the time of treatment to 
a minimum, will more than compensate for the expense of cutting the ties, 
saj, four months in advance, which in this climate is enough to put 
them in good condition. An examination of a lot of ties taken out of a 
cylinder after treatment will show, that while the oil consumed will aver- 
age, say, li gallons to the cubic foot of timber in the cylinder, some of 
the ties are entirely saturated, and others have received the oil only to a 
certain depth from the surface, leaving the heart in its natural condition ; 
a want of uniformity to be explained only by differences in seasoning, 
and differences in the grain of the wood in different trees. The latter 
cause is a peculiarity which will probably be found incident to every 
variety of timber to a greater or less extent, when exposed to this test 
It is not easy to secure uniformity of treatment, for, if the pressure 
is continued until all of the timber in the cylinder is saturated, there 
will be a consumption of from 7 to 9 gallons of oil to the tie, which is 
much more than it is deemed necessary or profitable to use in cross-ties. 
It is desirable to ascertain what depth of penetration of a preservative 
is necessary (less than complete saturation) to insure protection. 

Oonceming this we have the following experience : A lot of short- 
leaf pine ties were treated for this company and placed in the track in 
1875. They were treated in doable lengths and cut in two to be used, 
dimensions, T x 9"', 9 feet long. About ten per cent, were not treated 
through, and an area of from 2 to 4 inches in diameter of natural wood 
was thus exposed at one end to air and moisture. These ties are now all 
perfectly sound where the wood received the oil, but decay commenced very 
soon at the untreated exposed ends, and has penetrated in ai thai end only 
to an extent varying in length in proportion to the size of the area ex- 
posed. Where the surface was 4 inches in diameter the hollow extends 
30 inches ; where only one inch in diameter the decay reaches about 11 
inches. 

It is fair to infer that if these ties had been treated in the same manner 
in single lengths there would have been no decay, and the untreated 
parts would now be sound. 



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344 

The timber has been hardened bj this process, and shows as yet no 
serious wear. It would have been utterly worthless in two years had it 
not been treated. 

Failures in the use of preservatives are most probably often in conse- 
quence of failure to secure the presence of the material in the wood, 
as it is only by frequent and careful tests while the work is going on 
that one can know the character of it, and that it is being well done. 

Should you desire any further information in regard to oar methods 
of treating timber, I shall be pleased to furnish it, as far as I can. The 
above is an outline only, and I have suggested some points for your con- 
sideration which I think are worthy of investigation. I will send you a 
treated block of the pine timber we are using. 

Yours respectfuUy, 

M. G. HOWE. 



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AMEEIOAlf SOOIETT OF CIVIL ENGINEEES. 

INSTITUTED 185 2. 



TRAlSrSACTIOISrS. 

MoTB.— This Society is not responsible, as a body, for the facts and opinions advanced in any 

of its publications. 



CCXLVII. 

(Vol. XL— October, 1882.) 



THE KYAN PROCESS FOR PRESERVATION OF 

TIMBER. 

ITS USE AND EFFECT AT FORT ONTARIO, NEW YORK, 

1839 TO 1882. 



Bj WiLMAM P. JuDSON, Member Am. Soc. C. E, 



The following statement of the nse of Kyanized timber for the revet- 
ment of the earth slopes of Fort Ontario, Oswego, New York, is prepared 
for the information of the American Society of Oivil Engineers, with the 
consent of the Ohief of Engineers : 

Fort Ontario is situated on the sonth shore of Lake Ontario, and 
commands Oswego harbor and the month of the Oswego River. It was 
first established by the English in 1754, and has, since that date, been 
maintained as an important position for the defense of the Lake 
frontier. 

Its rebuilding with Kyanized timber revetment was begun by the 
United States on August 5, 1839. The work was in charge of Lieutenant 
Danville Leadbetter, United States Corps of Engineers, who reported it 
as completed on September 30th, 1843. 



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346 

The Eyanized timber revetments conHisted of timbers twelve inches 
by twelve inches (12"xl2") and six inches by twelve inches (6" Xl2"), 
varying in length from thirteen and one-half {13 J) to twenty-seven (27) 
feet, standing at a slope of two on one (2 on 1), and with an earth back- 
ing. The lower ends resting upon siUs eighteen inches sqnare (18" x 18"), 
the npper ends capped with timbers twelve inches by eighteen inches 
(12'xl8''). 

The caps and lower sills, and a middle sill of 18" X 18" timber which 
was used with the longer sticks, were anchored to the earth backing by 
ties twelve inches square (12"xl2") and six inches by twelve inches 
(6" Xl2"), extending into it at various depths. 

The entire work contained about ninety -two thousand (92 000) cubic 
feet of timber, equal to one million one hundred and four thousand 
(1 104 000) feet board measure ; all of which was subjected to the Eyan 
process. The details of the application of this process to Fort Ontario 
are taken from the reports, letters and records of the work, which were 
made by Lieut. Leadbetter, U. S. Corps of Engineers, during its pro- 
gress, and which are now on file in the XJ. S. Engineer Office, Oswego, 
N. Y. 

No copy of the original instructions is accessible. In some points of 
detail upon which Lieutenant Leadbetter*s reports are not specific, the 
omissions are supplied from the records of Fort Niagara, where Captain 
William Smith-Frazer, Corps of Engineers, was, at the same time, using 
this process for a similar work. 

The process was designated as *' Eyan's patent for the prevention of 
dry-rot and the worm,'* and was a comparatively recent invention, having 
been patented in England in about the year 1832. 

It was, in 1839, the property of an English company, whose agents in 
the United States were F. & D. Samuel, of Philadelphia. 

The process consisted in immersing the timber in a solution of one 
pound (lib) of corrosive sublimate (H^CVq) in fifteen (15) wine gallons of 
water, in an open tank, for a period of time varying from fourteen (14) to 
twenty-one (21) days, or until the timber should be saturated. This was 
determined by observing a gauge within the tank, which indicated the 
amount of liquid absorbed. 

Licenses were obtained from the agents of the patentee by lieutenant 
Leadbetter and by Captain Smith-Fraser, the terms of which required 
that the timber should be treated in accordance with instructions for^ 



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347 

niflhed by the company ; that the corrosive sublimate which was used 
should be purchased at market rates from the agents ; and that a royalty 
of fifty (50) cents per pound should be paid to the agents on all corrosive 
sublimate so purchased. 

In order to immerse the timber, two tanks, each thirty (30) feet long, 
sixteen (16) feet wide, and four and one-half (4^) feet deep, were built of 
three and one-half (3^'') inch seasoned pine plank, the joints being 
caulked inside and payed with a composition recommended by the 
patentee. 

The planks which formed the sides, ends and bottoms, were drawn 
together by screw-bolts, and were then treenailed to sills and posts, 
which formed the outline of the tanks. 

A cistern, with capacity equal to about one-third (i) that of a tank, 
and a pump, were connected with the tanks, so that the latter could be 
filled and emptied at will, or the solution transferred from one tank 
to the other if desired. It was necessary to avoid the use of iron where 
it would come in contact with the solution, because of its affinity for the 
mercury. 

A crane was erected over the tanks to handle the timbers. The total 
cost of the plant was ($875) eight hundred and seventy -five dollars. 

The timber which was treated varied in size from two (2) inch plank 
up to sticks eighteen (18) inches square ; the lengths varying from eight 
(8) feet up to twenty-nine (29) feet. 

The timbers were all framed, fitted, and ready to set up, and were 
then placed in the tanks, where the several pieces were secured and 
separated by cleats in such manner as to permit the free circulation of 
the solution around them. Each tank would thus receive fifteen hun- 
dred and thirty-five (1 535) cubic feet of timber. The corrosive sub- 
limate was then dissolved in hot water and poured into the cistern, and 
water was added in the ratio of fifteen (15) wine gallons to one pound 
(ltt>) of corrosive sublimate. The solution was then drawn into the tank 
and the process repeated until the timber was submerged. Four thousand 
(4 000) gallons formed one charge. 

After an interval of fourteen (14) to twenty-one (21) days, when the 
gauge showed that the timber had absorbed five hundred and seventy- 
four (574) gallons of solution, the remainder was pumped out of the tank, 
the timber was removed and was placed in a shed to dry. The 574 
gallons of solution which had been absorbed contained thirty-eight and 



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348 

A pounds (38i^) of oorrosiye sublimate, which had been received bj the 
1 535 cubic feet of timber. That quantitj of corrosive sublimate, with a 
corresponding amount of water, was, therefore, restored to the solution, 
which was then ready for another charge. 

The actual strenght of the solution was ascertained and corrected at 
interval bj the use of a hydrometer, and by " the metallic test," whose 
details are not specified. No mention is made of the probable evapora- 
tion from the tanks, nor of any provision to prevent it. It is stated, 
however, that the solution was found to freeze at 25 degrees Fahrenheit, 
and that, in freezing, it rejected from the ice the corrosive sublimate, 
and thus increased the strength of the unfrozen portion. The workmen 
who were employed about the tanks became salivated, and showed the 
various symptoms of mercurial poisoning, so that it was necessary to re- 
lieve them frequently. Those who erected the timbers after they were 
dried, were much troubled by the action upon their hands and by the 
festers caused by slivers ; and steel tools used upon the timbers speedily 
lost their edge. 

The actual cost of treating one charge of 1 535 cubic feet of timber* 
was as foUows, viz. : 

Pro rata cost of plant, its total cost being $875 $14 58 

Cost of 38 A lbs. cor. sub. in N. Y., @ $1.35 51 70 

Transportation on ditto from N. Y., @ 9 mills "^ft 35 

Royalty on ditto, @ 50 cents "^ ft 19 15 

Labor of handling timber, etc., @ 75 cents per 10 hours 25 00 

Total cost for treating 1 535 cub. ft $110 78 



Equal to seven cents two and i^ mills (.0722) per cubic foot, or $6 
per thousand feet board measure. 

The actual cost of the timber, delivered on the ground, was from 
($5) five dollars to seven and one-half ($7.50) per 1 000 feet board meas- 

* The present cost of similar work would be as follows : 

Pro rata cost of plant, its total cost being $1 780 |M 06 

Cost of 383-10 lbs. cor. sub., @ 55c 21 00 

Labor, handling timber, @ $1.50 for ten hours 60 00 

Estimated total cost of treating 1 535 cub. ft $108 06 

Equal to 6.5 cents per cubic foot, or $5.42 per thousand feet board measure. 
The present cost of similar timber, in its natural state, delivered on the same ground 
would be fifteen dollars ($15) per 1 000 ft. B. M. 



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349 

nre, according to size, the average cost being 9^ per 1 000 feet board 
measure. The expense of Kyanizing the timber was therefore just equal 
to its original cost. 

The patentee did not recommend the use of any especial species of 
timber, and hemlock was chosen for the Fort Ontario work because of 
its cheapness. It was, on this account, used for nearly the entire work, 
the only exceptions being a few sticks of basswood, beech and maple, 
which were received among the mass of hemlock. 

Under date of June 24, 1844, Lieut. Leadbetter reported regarding 
the work just completed : "Its appearance does not indicate the dura« 
bility which was hoped to be attained by the Kyanizing process. The 
solution of corrosive sublimate has always been kept to the full strength 
and the timber has generally been immersed longer than prescribed by 
the directions of the patentee. None of it has been standing quite four 
(4) years, and, already signs of decay are exhibited on the surface of the 
most perishable varieties " (t. c, the basswood, beech and maple referred 
to above). * ♦ ♦ » '* Presuming it to be very 

doubtful whether the interior of sticks of a foot square was in any degree 
affected by the solution, I have been expecting the appearance of fungi 
in the sun-cracks and have not been disappointed. 

" So far as I have observed, all these indications of decay are, as yet, 
confined to the more perishable kinds of wood, such as basswood and 
maple, a few sticks of which are found among the hemlock. 

'* But the latter, when unprepared, is not durable, and from the in- 
dications furnished by the others, this can hardly be expected to last 
beyond its natural duration. 

•* The whole of it is in contact with earth, the most unfavorable posi- 
tion, and the actual decay observed has been at the surface of the 
ground." ******** 

This quotation shows that the application of the Kyan process at Fort 
Ontario was then regarded as an experiment. 

The merits of the method are only to be determined now, by an ex- 
amination of the remaining parts of the work—forty years after its 
completion. 

Nine-tenths (^) of the shorter timbers are still standing, and about 
two-fifths (i) of the upper halves of the longer timbers, with their cap 
timber, are still in position ; the lower parts having been removed during 
1863-1868, to make way for other constructions. 



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350 

Bat enough of the timber remains to give ample evidence upon the 
subjeot in hand. 

The onlj timbers whose lower ends now rest upon or below the sur- 
face of the ground, are the shorter ones before mentioned. 

These, in general, keep their form and place perfectly, and retain 
the twelve or more feet of earth behind them. 

But, of one hundred which were examined, all show bj the presence 
of moss and fungi growing out of the season-cracks, that they are rotten 
for about six (6) feet from the surface of the ground upwards. Forty of 
the hundred show, by the same signs, that they are more or less rotten 
through their whole length ; while the remaining sixty (60) appear to be 
entirely sound excepting the lower six (6) feet as above mentioned. At 
other portions of the work, where these shorter timbers have been 
recently heaved away from the earth behind them, and where an ex- 
amination of the back of the timbers which has rested against the earth 
backing, is thus permitted, it is seen that the upper halves of the sixty 
(60) per cent, which are sound, show no material difference between the 
side which was toward the earth and that which was exposed to the 
air. 

The upper halves of the longer timbers which are still in position, 
show a better preservation than these shorter ones, having been much 
dryer ; eighty (80) per centum of their upper parts are sound through- 
out. 

Of the anchor-timbers which were buried in the earth backing, the 
upper tier which were three (3) feet beneath the surface of the bank, 
were of course the best drained, and ninety (90) per cent, of them 
are sound. The lower tiers were more moist, and about fifty (50) per 
cent, only, of their exposed ends are sound. No material difference is 
to be observed between the preservation of the six-inch by twelve-inch 
(6"xl2"), andof the twelve-inch square (12"xl2") timber. But the 
eigh teen-inch square (18"xl8''') middle sill shows rot much more gen- 
erally, and in some parts is almost wholly gone. Its own weight and 
that of the timber and earth above it, being, in such cases, only sup- 
ported by other constructions which have been built in front of it. 

These remarks apply only to hemlock, whose open, loose grain seems 
to be especially well calculated to receive the solution. The only sticks 
of beech and maple which can now be found, are wholly rotten, except 
an exterior shell of about i-inch thickness, a portion which remains. 



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351 

No pine was used in the work. 

At the same time that the work at Fort Ontario was in progress, 
similar Ejanized revetments were also building at Fort Niagara at the- 
month of the Niagara Biver, and at Fort Wayne, near Detroit, Michigan. 
Both of these works have since been rebuilt with masonry, and are in 
charge of this office. 

The same process was used in their construction as is herein described^ 
aud the general situation of the revetments was similar to that of Fort 
Ontario. 

This statement as to the process, therefore, applies to those works 
also. 

At Fort Niagara, no vestige of the timber revetment remains. At 
Fort Wayne, the remainder of the timber revetment which is still 
standing is wholly of red cedar. It is generally sound and shows no 
evidence of having been Eyanized. 

Specimens of the Fort Ontario timber, marked to indicate the por- 
tion of the work from which they are taken, are sent herewith. 

SuiOfABT OF BbSULTS AT FoBT ONTARIO : EyANIZBD HeMLOOK TiMBBB 

WITH Eabth Baoking, exposed roB Forty (40) Years. 

All timbers whose lower ends rest upon the surface of the ground, 
are rotten for (6) feet, from the foot upwards. 

Above this line of general decay, forty (40) per centum are rotten 
enough to impair their strength, and the remaining sixty (60) per centum 
are sound. 

Timbers which are buried in well-drained earth, which forms the 
upper part of a made embankment, five (5) per centum are rotten, five 
(6) per centum are impaired, and ninety (90) per centum are sound. 
Similar timbers, buried in base of same embankment, forty (40) per 
centum are rotten, ten per centum (10) impaired, and fifty (50) per 
centum soand. 

Of timbers entirely above surface of ground, eighty (80) per centum 
of the tops are sound. 

These observations apply to timbers twelve (12) inches square and 
smaller. Larger sizes show less favorable results . 

Eyanized beech and maple timbers are rotten except a shell. 

These results are shown in the following : 



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352 
TABLE I. 



LOOAXIOH DC WOBX. 



Lower 6 feet of timbers which rest on sarfiftce of 
ground at the foot of slope 



Rotten. Impaiskd. 



Soum). 



100 per ct. ; 



20 •• '20 per ct. j 60 per ct. 
5 " ' 6 " 1 90 " 



Upper 6 feet of the same timbers 

Timbers bnried in dry earth 

" inmoist earth 40 " ! 10 " 60 

Tops of timbers which are entirely above surface of 

gr jund at top of slope 10 " 10 " 80 



The prooess does not increase the difficulty of working the timber 
after it is thoroughly dried, nor appreciably change its appearance 
except to make it a shade darker, and of slightly less specific gravity* 

That the Kyanized timber is more rigid and is of greater transverse 
strength than similar timber in its natural state, is shown by the follow- 
ing record of tests which have just been made. 

Four specimens of sound timber were taken from different parts of 
the work. 

These were split to insure straight grain, and two sticks, each one 
inch square and twenty inches long, were made from each specimen. Of 
these, one stick from each specimen was tested ; the duplicates are sent 
herewith. Similar specimens of timber in its natural state, cut in 1880, 
from the same forest as was the Eyanized timber, and two (2) years sea- 
soned, were tested at the same time. 

In testing the specimen, the stick was laid, without fastening, upon 
timbers which were placed twelve inches apart 

A box was hung from the centre of the specimen by the bight of a 
soft rope I -inch diameter, and the breaking weight was applied gradu- 
ally, during a period of five minutes, by pouring sand into tlie box. 



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353 
TABLE rr.— Kyakized. 



No. 

OF 
8PK0. 


Location ik Wobk fob 40 Yeabs. 


Dkfuectioms at Cemtbe nr 
DscncALs OF Foot. 


Bbbax- 

IHG 

Wexobt 


100 lbs. 

.00. 

.003 

.003 
.005 


200 lbs. 

.010 

.005 

.005 
.009 

.007 


300 lbs. 

.014 

.008 

.007 
.012 

.010 


4001bfl. 

.023 

.012 

.013 
.018 

.017 


1 


npi>er end of timber, whose lower end 
rested on surface of ground and was 
rotten 


415 lbs. 


2 


Exposed end of timber which was burled 
in dry earth 


556 " 


3 

4 


Upper end of timber which stood entirely 
above snrfiico of ground and was sound. 

Upper cap timber on top of No. 3... 

Mean results. • 


467 •• 
474 " 




.004 


478 lbs. 









Natural State. 



No. 

OF 

Spec. 




Decimals of Foot. 


Bbxax- 

ma 
WsiaHT 


100 lbs. 


200 lbs. 
.011 


'300 lbs. 400 lbs. 

t 


5 




.006 


1 .016 1 


400 lbs. 


6 

7 


Cut from same forest as above specimens, 
and seasoned for two years. 


.007 
.004 


.011 
.008 


; .015 j .029 

; w* j 


406 '* 
384 •• 


8 




.003 


.008 


.012 ; .020 


404 '• 




Mean results 


.005 


.009 


. .014 ! .025 

1 


399 lbs. 







The effects which are produced by Ejanizing seem to be the resnlt of 
a chemical combination of the corrosive sublimate (Hg GI2) with the 
albnminous principle of the wood ; the action being similar, in a vege- 
table way, to the tanning of leather. 

It may be determined whether the wood is satnratd throughout, by 
applying hydro-sulphuret of ammonia, S (NE4) B — which turns 
black upon contact with the mercury. 

No portion of this work at Fort Ontario was placed in a position ana- 
lagous to that of an ordinary trestle, which is the sort of structure to 
which the process is best suited. But an examination of this work indi- 
cates that Eyanized hemlock, (and probably Canada white pine also) if set 



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864 

up 80 that there should be a free oircoktion of air about it, awaj from 
oontaot ^ith moist earth, and with its bases and joints so formed that 
water would not lodge in them, would be eighty (80) per oentum sound 
after forty (40) years. The use of the process is not recommended for a 
work which will be liable to continuous moisture. 

It has been suggested that the amount of corrodve sublimate could 
be advantageously increased by forcing a solution of greater strength 
into the timber, and this modification of the process would be necessary 
if hard wood were to be treated. 

It is not, however, considered that the process would be effective 
Against moisture under any circumstances, and the solution herein de- 
scribed is thought to be of ample strength for a dry situation, if the wood 
is thoroughly permeated by it 

A full and interesting article upon the subject of Eyan's process, may 
be found in the first volume of the Transactions of the Boyal Engineers, 
showing what was originally expected from its use, and also giving some 
•of its first results. 



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S65 



DISCUSSION 

ON THE REPORT OF THE COMMITTEE ON THE 
PRESERVATION OF TIMBER, 

AT THB 

CJONTENTION OP THB SoCIBTY AT WASHINGTON, D. C, MaY 16tH, 1882. 



Mekdbs Cohen, M. A. S. C. E. — Mr, Chairman^ — In this disons- 
sion it is perhaps well to get at the causes of the abandonment of the 
preserving processes, and as I was in charge of the Lehigh and Susque- 
hanna Railroad, upon which many Bumettized ties were laid down, and 
where the process continued until I found it expedient to suspend it, it 
seems fitting that the cause of its discontinuance should be stated. 

Whilst there had not then been time enough to test the ultimate dura- 
bility of the ties so treated, there had been ample opportunity to establish 
the fact that inferior timber, such as g^m and hemlock, quite unsuitable 
in its natural state for cross-tie purposes, was rendered tough and ser- 
viceable, and quite available. 

The abandonment of the process on this road was due entirely to the 
fact that the location of the yard and the disposition of the apparatus 
therein had ceased to be favorable for economical handling. The ties 
were, therefore, costing too much, and the ground was wanted for other 
purposes. 

Under these circumstances the process was suspended for the time 
being, and the apparatus removed to a more convenient locality, where 
it was intended to arrange ample facilities. 

The road passed shortly thereafter into the hands of lessees, and 
under the change of management the process was not resumed. 



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366 

A. GoTTMEB, M. Am. Soo. C. E.— Fifteen to twenty years ago Mr. 
L. B. Boomer, in Chicago, preserved the timber used in Howe trasses 
by the Baraettizing process. I have seen many bridges, the timber of 
which was treated by that process. The apparatus and manipulations 
were similar to those used in other processes. 

A boiler or tube 60 to 80 feet long, and about 6 feet in diameter, into 
which the timber was run on cars ; by steaming then the sap was ran 
out of the timber, and a vacuum pump employed to accomplish it more 
thoroughly ; then the boiler was filled with a solution of sulphate of 
zinc, and a high pressure applied to force it into the timber. Timbers 
treated this way, when left unprotected from the weather, lasted from 
15 to 24 years. The Burnettizing process is a good one to a certain ex- 
tent. As long as the solution remains in the timber it will protect it 
against rot ; but the trouble is that as the sulphate of zinc is soluble 
in water, it is in time washed out of the timber, when left exposed to 
the weather, and the timber is then left in a worse condition than if it 
had not been treated at all. This is the only objection I have against 
this process. 

The Thilmany process, which I know from my own observation, 
seems to me to improve on this point by using a double treatment 

This process treats the g^een timber, first in the same manner as 
described before, with a solution of sulphate of zinc or sulphate of 
copper. 

After this first treatment the timber is subjected to a second treat- 
ment with a solution of chloride of barium. This solution forms with 
the first one in the interstices between the fibres of the wood an in- 
soluble substance of sulphate of baryta and chloride of zinc. This pro- 
cess has been tried for some years in the Navy Yard in Boston for 
preserving timbers for the United States Navy. The Wabash, Lake 
Shore and Michigan Southern and New York, Pennsylvania and Ohio 
Railroads have used ties treated by this process for some years, and I 
have seen ties of all kinds of wood, as pine, beech, burr oak, hemlock 
and po|iar in the track of the Pittsburgh and Cleveland Bailroad at 
Cleveland, which were then about ten years in the track and perfectly 
sound. A stick 12" x 12"— 40 feet long, has been preserved by this pro- 
cess and cut through in the middle, and the crystals of the baryta could 
plainly be seen in the section. 

T. Eglbston, M. Am. Soo. C. E.— In the early days of the Union 



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367 

Pacific Railway, at the time that they had built only about thirty miles, 
I was attached to that company as an expert, and was witness to nearly 
all the wonderful feats that were accomplished in the construction of 
that road for some months ; one of these was the procuring of ties for 
the road previous to its reaching the base of the Rocky Mountains. 
These ties were made of cottonwood, in many of which a spike could be 
driven, but could no more be held than it could be held in a sponge. 

These ties cost fifty cents apiece delivered, and if I remember cor- 
rectly — for this was in the year 1864-5— it cost $1 each to preserve the 
ties, which were treated by the zinc process. 

The works were located on the bottoms at Omaha, and the road 
started from Omaha on these preserved ties. It was quite possible, after 
the ties had been treated, to drive the spikes in such a way that they 
would hold . Many of these ties were used between Omaha and the 
Rocky Mountains, where there of course was no difficulty in getting 
hardwood ties at a low price. 

If it had not been for this method of treating the timber, I doubt 
very much whether the road from Omaha to the Rocky Mountains could 
have been built, for I was told that the best cottonwood tie was uselesa 
at the end of a year. When the road reached the Rooky Mountains, I. 
was told that all these preserved ties, which lasted, as I remember, about, 
three years only, were taken out and replaced by hard wood. 

J. B. Francis, Past President Am. Soc. C. E. — ^As to the effect of the- 
corrosive sublimate used in the process of Kyanizing on the health of" 
the workmen employed in the process, my experience has been entirely 
different from that stated by Mr. Judson. With a use of it commencing 
in 1848, and continued to this time, with an interval, I have never 
known a case of salivation caused by it ; the workmen often get into, 
the tanks containing the solution, with bare feet, without any injurious; 
effects ; indeed, they have an idea, whether well founded or not I ami 
unable to say, that it heals sores ; one man with sore eyes got some of 
the solution in them, giving much pain for a time, but it was said it 
cured them. I recollect only one other case where any suppose^ 
injurious effect was produced ; in this case the man was engaged ii\ 
dissolving the corrosive sublimate in water maintained at the boiling 
point in an open vessel by free steam ; from breathing the escaping 
steam while stirring up the undissolved salt he was somewhat affected, 
but no serious trouble followed. 



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358 

There is one important point that I think has not been folly breast 
ont in this discussion. I refer to the preservation from rapid decay of 
s6me kinds of wood that are naturally so perishable as to be almost 
worthless unless treated by some antiseptic process. I have specimens 
of Cottonwood, Eyanized nearly twenty years ago, which have been in the 
ground ever since, and are still sound, the wood retaining its strength 
and color, while other specimens, not treated, and under the same ex- 
posure, have so completely decayed as to become nothing but black 
mould. 

I presume creosoting, and perhaps some other processes, would have 
been equally effective. 

CiiEMBNs Hebsohel, M. Am. Soc. C. E.— It is very evident that any 
process for preserving wood, to achieve its object, must have been well 
done. Bat beyond this, the testimony seems to show, that even when 
ordinary effort was made to carry out some of the processes in a good 
way, a portion of the timber treated did not resist decay as well as it 
should have done. How then are we to know whether a given stick of 
timber has been properly treated ? I suggest that more attention be 
paid to finding the means of testing the amount of preservative absorbed 
per cubic foot of a given stick of timber. 

The art of testing materials is becoming more and more an important 
branch of the business of the civil engineer ; witness tests of iron, of 
•ement, bricks and other substances now commonly made. Nor are we 
usually satisfied in these cases of iron, steel, cement, bricks, &c., with 
purchasing on the reputation of the manufacturer, or with having the 
material manufactured under inspection. ''The proof of the pudding is 
in the eating of it,*' and so we test the finished product I think this 
should be done in the case of treated woods. I am satisfied that were 
methods in general use for testing preserved or treated timber, the 
various processes of preserving timber would be more sought after than 
they now are, and that the use of treated wood, for certain purposes, 
would become general. I have had difficulty in finding any one, whether 
chemist or not, that could test wood after treatment by any process, and 
for this and the reasons abeady given, call attention to the subject 

T. EaiiBSTON, M. Am. Soc. G. E.— The time of the year in which 
wood is cut has as much to do with its strength and preservation as any 
other one thing. This matter has been very much neglected in this 
country, but a great deal of attention has been paid to it in Germany, 



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859 

and it maj not be withont interest for me to give a short synopsis of the 
report presented after experiments made by that government lasting over 
twenty years. 

They show that the season of cutting has not only to do with the 
present value of the wood for commercial purposes, but also with the 
time it will last 

Four pine trees grown on the same soil, and of the same age, were 
cut at the end of December, January, February and March, respectively. 
They were all squared with the heart in the centre, 9.42 metres by 0.157 
m. by 0.131 m., and were carefully dried in the same way, and tested for 
flexion. That cut in December sustained the greatest weight, that cut 
in January sustained 12 per cent, less, that in February 20 per cent, and 
that in March 28 per cent. Pieces of the same age were cut in Decem- 
ber and the last of March, and were made into posts 0.105 metres in 
diameter. After drying they were driven into the ground 0.94 metres. 
Those cut in December were good after sixteen years, those cut in March 
after the sap had begun to rise, broke short off after being used three 
years. Of pieces cut at the same time and buried in moist earth, those 
cut in December had some sound parts after sixteen years, those cut in 
March were rotten through in eight years. The same wood was used for 
stable flooring ; that cut in December lasted six years, that cut in March 
was good for nothing at the end of two. Felloes and wheels were made 
of beech cut in December and March ; those cut in December were good 
after sixteen years, those cut in March were worn out at seven. In order 
to ascertain the effect of the season upon the porosity of wood, four oaks 
entirely similar were cut at the end of the same four months, December, 
January, February and March, respectively, and at the same height 
above the ground. A disk was cut out of each which was 0.105 metre 
in thickness, and around this a rim of sheet iron 0.157 metre high was 
fixed and made perfectly tight . About two liters of water were poured 
into each of these four vessels. The vessel whose bottom was made in 
December allowed no water to pass ; the one cut in January showed 
drops at the end of forty-eight hours ; the one cut in February let out all 
the water in forty-eight hours ; the one cut in March held it only two 
and a half hours. To decide the question of porosity still further, staves 
were made from oak in December and January ; vessels were then made 
of these with the greatest care, which contained about three hektoliters 
each, and after drying and cleaning they were filled with new wine and 



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360 

left for one year. The one out in December lost 0.14 Uteris, while that 
out in January lost 7.2. 

It seems to be apparent from these faots that any wood which is cat 
for the purpose of being preserved must be cut at the season of the year 
when it will be most likely to retain the materials used for preserving, 
and thus preserve it under ordinary conditions. No attention has been 
paid to this matter in our own country. 

There seems to be no doubt that wood cut after the sap has started 
has less value than that which is cut between the fall of the leaf and that 
time. A series of experiments ought to be made on this subject, and it 
is for the interest of great railroad corporations to ascertain how far the 
wear of their ties is a£fected by the time when the wood is cut. 

E. B. Andrews, Assoc. M. Am. Soc. G. E.— In answer to an enquiry 
as to the economy of using preserved ties, Mr. Andrews said: The ques- 
tion of the extended use of preserved timber must be settled on the basis 
of true economy, i. e. , not first cost alone, but the cost during a term of 
years. If it can be shown that preserved ties at an enhanced cost will 
wear enough longer to pay the increase of first cost or more, the advan- 
tages of an undisturbed road-bed alone would be an urgent reason for 
their adoption. 

The following calculations, based on the relative cost of oak ties and 
oreosoted soft wood ties in New York at the present time,' seem to me 
pertinent to the question, and deserve the careful consideration of en- 
gineers in charge of railroads. I assume 16 years as the probable length 
of life of creosoted ties, the average life stated by the engineers of the 
principal railways in England, where the traffic, in amount and weight, 
will compare with that of the roads centreing at New York, i. c, almost 
constant. 

Example — Relative cost per mile of track of oak ties, @ 80 cents, and 
creosoted soft wood ties, @. 90 cents each. 



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361 

July 1, 1882. Cost of 2600 creosoted soft wood cross-ties (a, 

90 cents each, for one mile of track $2840 00 

** Compound interest at 6 per cent, for eight years 
(the outside life of oak ties), @ 6 per cent, per 
annum 1389 56 



3729 56 



July 1, 1882. Cost of 2600 oak ties, @ 80 cents, . . . 32080 00 
Comp. int. for 8 years, (a. 6 per cent 1235 15 



3315 15 



July 1, 1890. Cost of 2600 creosoted soft wood ties at the end of 
8 years' service, already in place, and sound and 
good for 8 years more $414 41 

'* Cost of 2600 new oak ties to replace 

those laid in 1882, @ 80 cents each, $2080 00 

*' Cost of transportation and relaying 

new ties, @ 15 cents each 390 00 



$2470 00 
Comp. int. for 8 years @ 6 per cent. 1821 68 



$4291 68 



" Comp. int. on cost of creosoted ties, 

$414.41 for 8 years, @ 6 per cent. . 246 02 

July 1, 1898. Balance in favor of creosoted soft 

wood ties per mile of track 3631 25 



$4291 68 $4291 68 



If it be urged, that with the actual condition of road-beds in this 
country, and the severe wear to which ties are exposed in consequence 
of the heavy rolling stock used, creosoted ties will not wear 16 years, I 
answer : 

The experience on the Central New Jersey Railroad with creosoted 
ties during six years under very heavy traffic is, that they are perfectly 



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362 

sound and with no apparent catting under the rails, and it is fair to as- 
sume they will be so after two years' more service, i.e., a mile of track 
will be tied with sound, serviceable ties after eight years* service. At 
that time a mile of oak ties must be relaid. 

The annual cost of an oak tie, at 80 cents first cost, with compound 
interest, is 20.6 cents, or $536.71 per mile of track. Hence, if creosoted 
soft wood ties will not last sixteen years, a railroad using them would 
realize an annual saving of $536.71 per mile of track for every year above 
eight daring which they do wear, on a cost of $414.41. This saving is 
certainly worth considering. 

A calculation of the relative cost of creosoted ties, at 90 cents, with 
oak or any other ties, which will last eight years, at 60 cents, shows a 
balance in favor of creosoted ties per mile of track of $843 in sixteen 
years ; and the difference would be still larger in favor of the creosoted 
ties in case the untreated ties do not last eight years, as very few will. 
The life expected from the heart of yellow pine ties, costing 60 to 65 
cents, which have been laid in large quantities during the past few years 
in the vicinity of New York, is only six years. 

I have based these figures on the presumption that the coet of rail- 
way cross-ties will be the same eight years hence as now. But as the 
price of ties at New York is now at least 20 per cent, higher than five 
years ago, the presumption is that with the continued demand and 
diminished supply, the price will grow steadily higher, the saving would 
be even greater than the above figures indicate. In fact, oak timber is 
rapidly disappearing all over the country, and is now almost unattain- 
able for ties. 

The wear of creosoted ties depends certainly to a degree upon 
the traffic of the road. As they will not decay on small roads 
where the traffic is light, I fully believe they will wear from twenty- 
five to forty years, but under the severe traffic of trunk roads with 
almost constant traffic of the heaviest class, they cannot be expected to 
last so long. From the statement made by the engineers of the English 
roads (see paper by John Bogart, Trans. Am. Soc. C. E., vol. VEEI, p. 
18), where the traffic is almost constant ; and from an examination of the 
ties sent by them to the Society as average ties, which had been in service 
from twelve to twenty-two years, it would appear, that on good road- 
beds with heavy traffic in this country, preserved ties would last from 
twelve to twenty years. 



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363 

Mr. HBRSOHEL—Are creosoted ties thoronghly saturated through the 
heart? 

Mr. Andrews— At a discuBsion on wood preservation by the Society 
of Arts, in London, June 1, 1860, in reply to a similar question, G. B. 
Bumell, F. G. S., F. S. A., said : " To be certain on that point, it would 
be preferable for parties wishing to apply this or any other preservative 
process, to entrust its execution to persons of experience and character," 
or, if you choose, have the work done under the supervision of your 
own inspector. 

But to answer Mr. Herschel's question pointedly, I beg to say there 
is no such test. Even eyesight will not enable one to determine. Creo- 
sote oil is dark colored and stains the wood, but the coloring matter 
constitutes only a part of the oil, and this, being coarser, is caught in 
the htrger or outer pores of the wood, while the lighter and possibly 
more effective parts penetrate deeper into the wood. Besides, no two 
sticks of wood, and, in fact, no two pieces from the same tree are exactly 
alike ; hence they will absorb the oil in an unequal degree. The creo- 
soter must not be blamed because every stick is not equally black. 
He undertakes to creosote timber, not to blacken it. Were it possible to 
completely saturate every stick, customers would not be found who 
would pay for it ; much porous timber will readily absorb 3 gallons or 
27 lbs. of oil per cubic foot, and I have injected 5 gallons. On the con- 
trary, dense white oak can with diflScnlty be made to absorb 3 to 5 lbs. 
per cubic foot. 

But, fortunately, we are not experimenting with an untried substance. 
For over forty years creosote has been in general use in England, and it 
is only fair to suppose that the quantity of oil which English engineers 
have settled upon as sufficient to protect timber in England, will suffice 
in this country, even if it does not blacken the wood through and 
through, i. «., 7 or 8 lbs. for use in the earth, and 10 or 12 lbs. when the 
wood is to be exposed in the sea. 

** To creosote" is simply to apply a mechanical process. Water in 
the wood, an obstacle to the admission of the oil, must first be removed, 
and then sufficient pressure must be used to force the oil in. It is un- 
wise for engineers to demand the injection of a larger quantity of oil 
than the density of the wood they specify will allow. It would be wiser 
to specify such varieties of wood as will readily take the quantity of 
oil which is known to be efficacious. White oak and the heart of pitch 



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364 

pine are the best for use when nnpreserved, bnt it does not follow that 
they are the best for creosoting. Bed oak or black oak, porous varieties, 
are strong enough for most purposes, when sound ; oreosoted thej will 
always be sound and will last longer than white oak, because many pieces 
of white oak refuse the oil altogether. 

Porous yellow pine, comparatively free from pitch, will drink up the 
oil much more freely and evenly than pitch pine, and will give a much 
better result, because creosote is a much better preservative than pitch ; 
and all porous woods are cheaper than dense, indestructible varieties. 



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AMEEIOAN SOCIETY OF CIVIL ENGINEERS. 

INSTITUTED 1863. 



TRi^LNSAOTIOlSrS. 

MoTB.— Tbia Society is not responsible, as a body, for the &cts and opinions advanced in 
any of its publications. 



CCXIiVIII. 

(Vol. XI.— November, 1882.) 



ON THE INCREASED EFFICIENCY OF RAILWAYS 
FOR THE TRANSPORTATION OF FREIGHT.* 

By Wm. p. Shinn, M. Am. Soo. 0. E. 
Bead Deoembbb 20th, 1882« 



At the Louisville convention of this Society, held in May, 1878, a 
distinguished civil engineer and member of this Society, quoting from 
an address delivered by him before the Chamber of Commerce of the 
City of New York, took the ground that the New York State canals 
formed the only line of transportation to tide-water, for the cereal pro- 
ducts of the great West, that could compete with the Welland Canal and 
St. Lawrence Biver, and that a ship canal connecting the waters of the 
great lakes with the Hudson Biver was necessary to the *continnance of 
the commercial supremacy of the City of New York. 



* Host of the data for this paper were oollected and prepared for the forthooming report 
on Internal Commerce, of Hon. Jos. Nlmmo, Jr., Chief of Bureau of Statistics of the Treiiniry 
Department, with whose consent they are presented before the American Society of Civil 
Engineers in advance of the publication of his report. 



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366 

In the course of his remarks the gentleman said : *' I stated tha£ 
three-fonrths of all the freight from the West to tide-water went by two 
camtis, chiefly by the Erie ; that left but two million tons to be carried 
by the four trunk railroads. ♦ ♦ * Although the quantity of freight 
is large, during the year these roads together moved eastward only two 
million tons of through freight, which is the class I allude to." 

The year referred to was 1872. 

I replied to the above by stating that the ultimate capacity of a rail- 
road was, to a great extent, a matter of speculation, but that with a 
double track, devoted entirely to freight traffic, there would be no diffi- 
culty^in carrying one thousand (1 000) tons per hour, or about 7 200 OOO 
tons per annum in one direction, and added: ** I will not attempt to com- 
pare the cost of carrying seven million tons on one railway with that of 
carrying (as alleged) two million tons on four railways ; evidently it 
would be much below the least sum already stated (by myself) as the 
cost on one first-class railway, namely, seven mills per ton per mile." 

I refer to this discussion to show that only nine years ago informa- 
tion regarding the capacity of railroads for traffic was very meagre, the 
popular impression as to their efficiency, compared with that of canals, 
being wholly erroneous. 

The gentleman referred to was in error even in his statement as to 
the transportation of cereals to tide-water in 1872, for it appeai-s (see 
Schedule A, attached) that of the grain transported to New York, 
60 724 027 bushels (say, 1 450 000 tons) were transported by canal, and 
37 686 167 bushels (say, 1 074 000 tons) were transported by raU, and 
that in 1873 the movement of grain by rail to New York exceeded that by 
canal. 

I have compiled from the report of the Bureau of Statistics on In- 
ternal Commerce for 1880 (pp. 160 and 184), the statement in Schedule 
A, showing the receipts of grain at New York, by canal and rail, from 
1871 to4880, and at Boston, Philadelphia and Baltimore from 1875 to 
1880, which shows how greatly the transportation of grain by rail to the 
Atlantic seaboard has exceeded that by canal since 1873. 

On page 179 of the Internal Commerce Report for 1880, I find a 
statement of the •* total number of tons transported on the New York 
State canals, the New York Central and Hudson Biver Bailroad, the New 
York, Lake Erie and Western Bailroad, and the Pennsylvania Bailroad, 
each year from 1855 to 1880." 



i 



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367 

As this statement ignores the distance that the tonnage was trans- 
ported, and is open to the objection of including the same tonnage more 
than once when the statistics are kept by divisions, I have prepared and 
attached hereto, as Schedule B, a "statement of comparative tonnage- 
mileage," or ** tons carried one mile on New York State canals, the New 
York Central and Hadson Biver Bailroad, the New York, Lake Erie and 
Western Bailway, and the Pennsylvania Bailroad, from 1860 to 1881, 
inclusive." 

This statement shows that in 1860 the "tonnage-mileage" of the 
three railroads was about equal, and amounted, in the "aggregate, to a 
little over three-fourths of that of the canals ; that in 1870 the three 
railroads averaged, each, about the tonnage of the canals ; and that in 1880 
they averaged, each, nearly double that of the canals, the tonnage of the 
latter being in 1880 the largest they ever had. 

Comparing the aggregate ton-mileage of the three railroads, we find 
that it was : 

Increateper cent, over 1860. 

In 1860 627 477805 

" 1870 2682603465 828 

" 1880 7 485 734038 1 093 

" 1881 8263038412 1217 

Evidently the " condition precedent " of this enormous increase in 
traffic was the existence of the products to be transported and a demand 
for their transportation, and we must look for the cause of these condi- 
tions in the improvement in 'popalation of the producing States, in the 
transportation facilities tributary to these railroads, and in some degree 
in the foreign demand for our products. 

Grouping the States into three classes, viz. : 

1. New York, New Jersey and Pennsylvania, in which the three in- 
dicated railroads lie ; 

2. The Northern Middle States, directly tributary to these railroads; 

3. The Northwestern States and Territories, more remotely tributary 
thereto; 

We find the population and railroad mileage to compare for the 
three periods as follows, viz. : (See Schedule C.) 



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368 



OBOUPS OW 8TATB8. 



1860. 



POPULATIOM. 



1870. 



1880. 



M".KK Baelboad. 



1870. 1800. 



First-S States - 7 458 985! 8 810 806' 10 497 579 9 709 13 963 

I I ' ' 

Second— 5 States ' 6 926 954 9 124 517 11 207 181 14 701 25 382 

Third— 6 States, 5 Ter-| 

4 027 956; 6 288 920 8 889 i 22 099 



ritones . 



2 244 382 



Total— 14 States, 5 Ter i 

ritories • 16 630 321 1 21 963 2771 27 993 680 , 33 299 , 61 444 



Total of United States. . ' 31 443 321 38 558 371 50 152 866 ' 52 914 93 671 

^_^^ i ,^ ^ J^ '^^ ^_ .:L, . _^___ ^ 

The following shows the prodaction of grain in 1869 and 1879, and 
the amounts exported in the fiscal years ending Jane 30, 1870 and 1880: 





U. S. Pboduction.— Bushels. 


EXPOBTED 


-BUSHEI^. 




1869. 


1879. 


1870. 


1880. 


Com 


874 320 000 


1 547 901 790 


1 392 115 


98 169 877 


Wheat 


260 146 900 


448 756 630 


17 907 442 


153 869 935 


Bye 


22 527 900 


23 639 460 


157 606 


2 912 754 


Oats 


288 334 000 


363 761 320 


121 517 


766 366 


Barley 


. 28 652 200 


40 283 100 


255 490 


1 128 923 


Buckwheat . . 


. 17 431 100 


13 140 000 






Other Grains. 






385 198 


1 272 028 











1491412 100 2 437 482 300 20 219 368 258119 883 
The following is a comparative statement of other leading exports for 
the fiscal years ending June 30, 1870 and 1880: 

1870. 1880. 1870. 1880. 

Pounds. Pounds. 

Wheat flour, bbls. ... 3 463 333 6.011 419 692 666 600 1 202 283 800 

Com meal, bbls 187 093 360 613 37 418 600 70 122 600 

Crude oil, galls 9 955 066 28 297 997 69 685 462 198 086 979 

Refined oil, " 97 902 505 367 325 823 636 366 282 2 387 617 850 

Naphtha '* " .... 5 422 604 18 411044 32 535 624 110 466 264 

Lubricating oU, galls 5 162 835 38 721 262 

Butter 2019288 3^236 658 

Cheese 57 296 327 127 658 907 

Beef 26 727 773 84 717 094 

Bacon and hams 38 968 256 759 773 109 

Pork 24639831 95 949 780 



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369 

Lard 35 808 530 374 979 286 

Tobacco ;. 186748881 215 910 187 

Cotton 958 658 563 1 822 061 114 



Total of articles above enumerated 2 798 440 017 7 527 483 890 

Grain, bushels 20 219 368 268 119 883 1 197 275 357 15 038 181 064 



Total of leading exports pounds, 3 996 716 374 22 566 664 954 

The exports of the articles enamerated show an increase from 

3 995 715 874 pounds in 1870 
to 22 565 664 954 pounds in 1880, 

Being 18 569 949 580 or 464/u per cent. 

The total exports of the United States * were valued for the fiscal 

year ending June 30th, 1870, at $392 771 697 

And for the fiscal year ending June 30th, 1880, at 835 638 658 

An increase in value of $442 866 961 

The exports of breadstufia, provisions and live animals * compare in 
value for the two years as follows : 

For Fiscal Years 1870. 1880. Increase. 

BreadstuflGs $72 675 495 $288 076 835 $215 401 340 

Provisions 28 283 143 127 043 242 98 760 099 

Live animals 1 045 039 15*882 125 14 837 086 



Total $102 003 677 $431 102 202 $328 998 525 

Referring to the increane in exports of these three classes, Mr. H. Y. 
Poor, in his Manual for 1881, says* : ''The enormous increase of our 
" foreign commerce, shown in the annexed statement (above quoted), is 
** due almost wholly to the increased exports of provisions and bread- 
" stuffs, the product of that portion of the country most distant from 
** market, and in which railroads have had their widest and most rapid 
" development. " **It will be seen (from the foregoing statement) that of 
« an increase (in value) of exports of $443 000 000, $329 000 000 was 
" made up of the products of the Western States, these being almost 
'' wholly due to the construction of railroads within them." 



* Poor's B. R. Manual for 1883, pp. IV and V. 



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370 

The prodnotion of cotton, anthracite coal, pig iron and Lake Super- 
ior iron ore compares as foUows : 

For 1870. For* 1880. Increase. 

Cotton— bales 3 114 592 5 761 252 2 646 660 

Anthracite coal— tons 16 182 191 23 487 242 7 255 061 

Pig iron— net tons 1866 000 4 295 414 2 430 414 

Lake Superior iron ore -tons. . 908 805 2 389 288 1 480 483 

The production of anthracite coal in 1881 was in excess of 1880 over 
5 000 000 tons, an increase wholly unprecedented. 
The movement of cotton ''overland*' was, for the 

year ending August Slst, 1870 * 350 416 bales 

Year ending August 31st, 1880 1 134 004 bales 

Being an increase of 783 588 bales 

The foregoing statements show clearly whence came the increased 
traffic, and it remains to consider the means by which the great increase 
in ** ton-mileage," shown in Schedule B for the three leading railroads, 

was made, from a movement in 1870 of 2 682 603 465 ton- miles 

to a movement in 1880 of 8 263 038 412 ton-miles 



Being an increase of. 6 580 434 947 ton -miles 

The ** ton-mileage" of 1880 being three and eight hundredths (Sf^) 
times that of 1870, and tlyrteen and seventeen hundredths (13 ^Vd) times 
that of 1860. 

The means by which this rapid increase in efficiency has been devel- 
oped may be considered under two general heads, viz. : 

Improvements in the physical condition of the railroads, such as : 

1. Improved track or *' permanent way," including bridge super- 
structure. 

2. Additional sidings, and second, third and fourth tracks. 

3. Increased capacity and strict classification of locomotives. 

4. Increased capacity of freight cars. 

5. Additions to terminal facilities. 
Improvements in the administration, such as : 

6. Improved methods of signalling. 



* Report on Internal Commerce of U. S. for 1880. p. 187. 



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371 

7. Banning looomotives ** First in, first out," and mnning freight 
trains at higher rates of speed. 

8. Consolidation of connecting lines ander one management by pur- 
chase, lease, amalgamation or otherwise. 

9. Bunning freight cars through from point of production to tide- 
water without trans- shipment. 

10. Issuing through bills of lading (or freight contracts) from West- 
em points of shipment to Atlantic and European ports. 

These will be referred to in their order. 

1. Qood ** permanent toay** is the necessary foundation of all suc- 
cessful and economical railroad management, and chief among the 
improvements of the last 11 years is the general introduction of 
steel mils. The discovery of Henry Bessemer of the pneumatic process 
of steel making, with the addition of spiegel-eisen suggested by Mushet, 
as improved and adapted for use in this country by the late Alex. L. 
HoUey, M. Am. Soc. C. R, enabling steel rails to be manufactured as 
cheaply as iron rails can be made from the ore, forms the very "comer- 
stone " of the great improvements which have taken place in railroad 
efficiency. 

The importation of steel rails (of crucible steel) was begun by the 
Pennsylvania Bailroad Company in 1863, with a trial lot of 150 tons, and 
the manufacture of *' Bessemer steel ** (so called) was commenced in 
1866, at Troy, New York, and in 1867 at Harrisburg, Pennsylvania, both 
under the personal supervision of Mr. Holley. 

Schedule D, attached, shows the number of tons of steel rails made 
in this country during each year, as compiled by James M. Swank, Sec- 
retary of the American Iron and Steel Association.* 

It will be seen that there were made of steel rails in this country in 

1870 34 000 net tons 

And in 1881 1 355 519 '* «« 

An increase of 1 321 519 ** ** 

And that the total amount of steel rails made in the United States to 

the close of 1870 was 53 425 net tons 

And to the close of 1881 was 5 171 699 •* 

Being an increase of 5 118 274 ** »• 

* Report of American Iron and Steel AssocUtion for 1881. 



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Miles. 


8 469 


3 218 


26 771 


12 127 


19 966 


5688 


68 808 


25 623 


6 522 


2 411 



372 

In addition to which there have been imported to Jane 30ih, 1881t 
about 1 000 000 net tons, all of which, amounting in the aggregate to 
6 171 699 net tons, have been laid in the tracks of railroads to the extent 
of about 60 000 miles of single track. 

Mr. Poor, in his Manual for 1882,* estimates that at the close of 1881, 
of 104 325 miles of railroad completed, having 130 536 miles of track, 
49 062 miles were laid with steel rail, being apportioned to the five grand 
divisions of the country as follows : 

Miles Bailroad. Miles Track. Steel Rails- 
New England SUtes .... 6 161 

Middle States 15 984 

Southern States 18 005 

Western States, etc 58 227 

Pacific States, etc 5 948 

Total 104 325 130 536 49 062 

The difference between the mileage of track now laid with steel, and 
the aggregate of steel rails made and imported, represents the rails taken 
up in consequence of failure or wear. 

Much discussion has taken place on the question whether steel rails 
of domestic manufacture are equal to the foreign made. Their eqaality 
has been pretty generally conceded since 1878, but their superiority has 
been demonstrated, in at least one case, on the New York Central and 
Hudson River Railroad, where there were laid in 1877 one thousand tons 
steel rails made by an American mill, and in 1881 Mr. P. H. Dudley, in 
running over the tracks of that railroad with his "dynograph car," 
which makes an automatic record of the surface and lateral alignment of 
each rail, found, to his surprise, pieces or stretches of track where the 
irregularities of surface were much below the average, and in every such 
case the track was laid with the rails referred to ; the balance of the track 
being mostly of English rails, many of them laid subsequently, and all 
equally well ballasted and cared for. 

The adoption of steel rails has generally led to the use of improved 
joints, better ballast, and more careful alignment and surfacing, aooom- 

* Poor's Manuftl of Rftilroads for 1882, pp. XVI and XVlf . 



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373 

panied by better drainage, as it is considered to be a much more **per' 
maneiU way " than when iron rails, requiring such frequent renewals, 
constituted the track. 

The Pennsylvania Railroad Company has added the '* finishing touch '* 
by sodding their slopes in cuts and making cement or artificial stone 
'* ditches," which are not filled up by detritus from the slopes by every 
shower. 

In wearing quality steel rails are greatly superior to iron, they having 
lasted, under reasonably heavy traffic, from 8 to 12 years. It is 
evident that their life is a function of the tonnage and wheelage rather 
than of time, and as tonnage increases, their duration in years must 
decrease proportionately. Enough is known to warrant the statement 
that with their use the cost pf ''keeping up track " and ** renewals of 
rails '* is reduced from 40 to 60 per cent, per ton-mile. 

2. The increase in second track and sidings has been very marked in 
the Middle States, where the railroads taken herein as types of efficiency 
are located. 

According to Poor's Manual, already quoted, they had track mileage 
as follows on December Slst, 1881, viz. :* 

Railroad Second Track Total 

Miles. and Sidings. Miles. 

New York 5 981 4 429 10 410 

New Jersey 1663 1323 2 986 

Pennsylvania i 6 748 4 362 11110 

Three States .♦ 14 392 10 114 24 506 

Being an average of 1 mile of second track and sidings for each 1 1^^^ 
miles of railroad. Some of the railroads, notably the New York Central 
and Hudson Biver and the Pennsylvania, have laid third and 
fourth tracks, (using when they have four) two tracks exclusively 
for freight trains, thus permitting them to move at a regular 
rate of speed without detention from passenger trains. Such tracks are 
included above under the term "second track.*' They add greatly to 
the efficiency of the railroad for freight traffic, and must be gradually 



* Poor's Manual of Ballroadt for 1882, pp. XVI. and XVII. 



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374 

ext^idedas freight traffic increaseB, pArticnlarlj where the passeoger 

traffic requires frequent trains. 

The capacity of a single track has probably nowhere reoeiyed ft 

greater deyelopment than on the Pittsburgh, Fort Wayne and Chicago 

BaQway, where was made on 4SS^ miles of railroad, of which bat 74^ 

miles were double track, and having 184 j^ miles of sidings and yard 

tracks*— 

Mileage of Passenger trains in 1881 2 015 298 

Do. Freight do. do 7 916 719 

Do. other do. do 320 897 

Total train mileage in 1881 10 252 9U 

Equal to trains both ways over whole road of — 

Passenger trains 2 151iVo» ^r P^r day 5i'A 

Freight trains 8 452iVo, ** SS^V. 

Other trains 342,«<rD. ** li% 

Totaltrains 10946iVb. ** 30iVo 

or over 30 trains each way per day for 365 days, excepting working 
trains, which are calculated for 313 days. 

3. Increased locomoHve capacity is primarily due to the introduction 
of steel rails, by making it possible to have heavy engines without rapid 
destruction of track. 

A rail has to be considered with reference to its strength as a beam, 
enabling it to carry the moving load from point to point of support ; 
and to its capacity to resist the rolliag friction of the locomotives and 
oars, having a tendency to produce lamination and abrasion. 

A material increase in both these particulars, oves iron rails,! was 
requisite before heavier equipment could be adopted than that used in 
1860. In 1863-'5, on the Pittsburgh, Fort Wayne and Chicago RaUway, 
under the management of that eminent civil engineer and railway mana- 
ger, John B. Jervis, Hon. M. Am. Soc. C. £., it was found to be advisable, 

* From Tenth Anntud Report of PennsylTanU Company. 

t Expertmentt and teats made by the writer in 1877, when Oeneral Manager of the Edgar 
Thomson Steel Works, of the comparative transrerse strength of iron rails (as then made, chiefly 
from old rails) with steel rails of like weight, appeared to warrant the conolasion that steel rails 
had at least double the transrerse strength of suoh iron rails, due partly to the better dispoBiUon 
of the metal in the steel rails for strength as a beam, but mainly to the greater homogeneity 
of the material. 



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376 

in order to preserve the track (of 60-ponnd iron rails) from too rapid deter- 
ioration, to adopt materially lighter equipment than had been previonslj 
used, and he bought engines for freight service having cylinders 14 x 22 
inches, weight on drivers 31 000 pounds, capable of hauling 12 to 16 
loaded cars ; and bnilt cars weighing but 16 000 to 17 000 pounds, carry- 
ing 20 000 to 24 000 pounds of load. This change proved immediately 
beneficial, and laid the foundation for the uninterrupted prosperity 
which the Pittsburgh, Fort Wayne and Chicago Railway has since en- 
joyed. As the track was laid with steel and otherwise improved, the 
adoption of heavier equipment became equally wise and proper, and the 
standard freight engine now built has cylinders 18 x 22 inches, weight on 
drivers 54 000 pounds, and draws 22 to 24 loaded cars. 

On the Pennsylvania Railroad, in 1871-'2, the standard freight 
engines had cylinders 18 x 22 inches, with drivers 50 and 56 inches 
diameter, weight on drivers 55 000 pounds (average weight on each 
driver, 9 166 pounds), and pulled by the dynamometer 12 500 to 14 000 
pounds as a maximum, at a very slow speed when just starting, and 
drew 18 loaded cars on the Pittsburgh Division. 

The present standard freight engine has cylinders 20x24 inches, 
with eight drivers, 50 inches diameter ; weight on drivers, 79 400 
pounds (average weight on each driver, 9 925 pounds) ; pulls by the 
dynamometer 20 500 pounds under similar circumstances to those above 
named, and draws 28 loaded cars on the Pittsburgh Division. 

The following statement shows the average tons freight hauled in 
freight trains on the railroads before referred to, for various years from 
1867 to 1881 : 

Statement of Average Tonnage op Freight HauiiED in Freight 
Trains on Railroads Named. 

Pennaylvama. 



N. Y. C. N. Y., MaiD Line Main Line P. cfc E. P., F. W. 
A 11. R. R. L. E. & W. Eastward. Both Ways. Div. A C. 



In 1867 












102 iS 


- 1870.... 








112 


118 




" 1875.... 


166 


134 




128 


164 




" 1880.... 


219 


218 


283 


184 


266 


160 AA^ 


*' 1881.... 


218 


218 


287 


186 


275- 


171 M 



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376 

Showing increased average train load, as foUows : 
On New York Central and Hudson River Railroad, from 

1875 to 1881, of 31 1^ per cent 

On New York, Lake Erie and Western Railroad, from 

1875 to 1881, of 62 A 

On Pennsylvania Main Line, from 1870 to 1881, of 66xS " 

On Philadelphia and Erie RaUroad, from 1870 to 1881, 

of 133 

On Pittsburgh, Fort Wayne and Chicago Railway, from 

1867 to 1881, of 66 A 

or an average increase of about 66 1 per cent, due to improved "per- 
manent way,'' permitting the use of improved machinery of greater 
capacity, and to more general ''back loading " of cars. 

Of the effect of improved track on engine repairs, suffice it to say 
that on the Pennsylvania Railroad the cost of repairs of locomotives per 
100 miles run was — 

In 1865 $16 45 

" 1870 • 9 13 

*• 1879 5 30 

«' 1880 7 02 

'* 1881 6 02 

while the effective capacity of the engines has been largely increased in 
the meantime. 

By strict classification of locomotives, much greater efficiency is 
reached with the same number. The Pennsylvania Railroad Company 
now has practically but two classes of freight locomotives. 

4. Increased capacity of cars, — ^For many years, say from 1855 to 1876, 
the standard capacity of freight cars was 20 000 pounds, although much 
more was frequently loaded on a car. About 1877 a few cars were built 
to carry 30 000 pounds, and since 1879 the standard freight cars built 
for the principal east and west lines of railroad have been constructed 
to carry 40 000 pounds. I am informed that the Pennsylvania Railroad 
Company has ordered the construction of some cars having 50 000 lbs. 
capacity. This increased capacity is obtained by using a somewhat 
heavier car body, or '* cargo box,*' with slightly heavier axles and 
journals. The comparative weight of a standard Pennsylvania Railroad 
box car, with its load, in 1870 and 1881, was as follows, viz. : 



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377 

Load 
Weiffhtof Weight of t,.. Per Cent. 

(Sir. S>ad. ^°^^- ofTotel. 

In 1870 20 500 20 000 40 500 

"1881 22 000 40 000 62 000 




Increase... 1500 20 000 21500 

The benefit both in efficiency and economy of cost from an increase 
of 30 per cent, in the proportion borne by the '* paying load " to the 
** total load *' is too obvious for comment 

The following statement shows the average tonnage of freight per 
.loaded car on the Pennsylvania Railroad and Pittsburgh, Fort Wayne 
and Chicago Railway for several years : 

Penna..R. R. P., F. W. A C. Ry. 

In 1867 7M tons. 

** 1877 IOjVo tons. 

"1878 lOM •* 

** 1880 ll,Vb *' 9i% " 

"1881 * 12iVq " lOA^ " 

This average includes many cars only partiaUy loaded with local 
freight ; the Pennsylvania Raibroad has a large local traffic, which is 
shipped in full car-loads, thus increasing their average load, which shows 
a steady and commendable advance, due to the increased use of cars of 
greater capacity. 

5. Increase in terminal facUUies, — These consist of depots and yards 
for receiving, loading, discharging and delivering freight, in yards and 
tracks for storing cars and switching, and in floats and lighters for trans- 
fer of cars and freight, grain elevators, stock yards, etc., which have 
been more than doubled in the aggregate since 1870. The increase is 
still going on, and the expenditure for additional terminal facilities will 
long continue to be a prominent item in the " Construction " or " Better- 
ment " account. 

Considering next the improvements in administration, we have : 

6. Improved methods qf^ signalling, — ^The " block system," which has 
been in use abroad for many years, was first adopted in this country on 



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378 

a large scale on the Penasylyania Bailroad. It oonsists in a diviaion of 
the road into sections or '* blocks " ifrom one to five miles in length, hav- 
ing signal stations at each end thereof, whereby bat one train is allowed 
upon any block at one time, and a following train is forbidden to enter 
a block until the preceding train has passed the next signal station and 
the fact has been reported back. Freight trains are sometimes allowed 
to follow on the same block, nnder restrictions as to time, being kept 
five or more minutes apart. 

A complete system of block signals ia absolutely necessary to the safe 
and effective working of a crowded track, and the adoption of the auto- 
matic electric signal, by which blocks or sub-blocks may be made every 
mile or half mile, will render railway travel much safer, and greatly in- 
crease the effective capacity of the lines. 

The subject of ''block signals'* and ''interlocking switches" has 
received much more attention in England than in this country, and the 
writer was told in 1876 of a "junction " in the North of England (what 
we call a '* crossing ") which was traversed by 720 trains daily, an aver- 
age of a train every 2 minutes, day and night. The Metropolitan 
(underground] Railway of London is a conspicuous example of an enor- 
mous traffic conducted with absolute safety under very unfavorable con- 
ditions by the use of a complete system of block signals. 

7. Running locomotives ** First in, first out," and running freight 
trains at higher speed, — ^Daring the early history of railroads, it was con- 
sidered essential to economy that freight trains should be limited to a 
very low rate of speed, and until recently they have been generally 
"scheduled" at a speed of 10 to 12 miles per hour, and limited to 15 
miles per hour as a maximum speed. 

The late J. Edgar Thomson, as President of the Pennsylvania Bail- 
road, in his annual report for 1867, referring to the proposed construc- 
tion of a low grade line for reaching economy in freight traffic, said : 
"The speed of the freight trains should not exceed an average of 6 
" miles per hour." When we reflect that this is but one-half faster than 
a man can walk, and that at this speed nearly twice as many engines and 
one-half more cars will be needed than would be required if the traffic 
were moved at an average of 12 miles per hour, its adoption seems absurd ; 
and yet Mr. Thomson was high authority, and with the iron rail tracks 
and wooden bridges then in use, high speed was very destructive to the 



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379 

saperstructure. But with better "permanent way" and iron bridges, 
higher speed became possible, and freight trains are now scheduled at 
from 15 to 20 miles per hour.* 

Until quite recently, every locomotive had its regular •* engineer," 
and when he slept the locomotive was idle. This was changed on the 
New York Central and Hudson River Bailroad some eight or ten years 
since with but indifferent success, by the adoption of the rule of " first in, 
first out, "for both locomotives and crews, so that the next crew in order 
takes the next engine in order, and by having many more crews than 
locomotives, nearly 50 per cent, more service is got from the latter, with 
leas deterioration caused by frequent alternations of heating and 
cooling. 

The Pennsylvania Kailroad Company, after carefully experimenting 
with it on their Middle Division, adopted it for their whole line in 1878, 
and the benefits of this system were first shown by its results in 1879, 
as will be seen by reference to Schedule E, giving the average miles run 
per annum by freight locomotives on the Pennsylvania Bailroad, and the 
average number of tons freight hauled by each from 1870 to 1881. 

It shows as the average of all divisions — 

Per Locomotive. Miles Run. Average Ton-Mileage. 

In 1870 , . . . 19 244 2 100 000 

•* 1878 20 000 3 000 000 

'* 1879 24 355 4 200 000 

**1881 27 644 5 100 000 

— an increase in mileage of 38 per cent., and in effective service of 150 
per cent, from 1870 to 1881. Of course, much of this latter increase 
is due to the use of more powerful engines and better cars, as before 
stated. 

8. ConsolidcUion of connecting lines under one management. — This has 
changed in a wonderful degree the condition of our ** railway system," 
and greatly to the improvement of its efficiency. Where in 1860 it was 
rarely that 500 miles of railroad were under one management, now from 
1 000 to 3 000 miles in one organization is the rule rather than the ex- 
ception. 

* The experimentB of Mr. P. H. Dudley wiib hla " dynogr&ph " car ahow that a speed for 
firelght traiua of 18 miles per hour requires less power and la more eoonomical of fuel than a 
alower rate of apeed. 



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380 

Schedule F shows the length of roads and the gross earnings in 1881 
of 13 of the principal systems, from which it will be seen that the 3 
''trunk line " systems controlled 10 113 miles of railroad, being 10 ^'e 
per cent, of the total mileage for which earnings were reported in 
Poor's Manual for 1881, and their aggregate gross earnings were 
$155 371 388, or 21 /o per cei^t. of the total earnings reported for 1881 ; 
while the 13 systems indicated had 44 627 miles of road, or 47 1^ per 
cent, of the mileage for which earnings were reported for 1881 ; and their 
aggregate earnings were $354 158 398, or 48iVu per cent, of the total earn- 
ings reported. 

The amount of negotiations, disputes, delays and general friction 
saved by having but 13 parties in control of these lines instead of 100, 
can scarcely be estimated, and this has been a potent factor in bring- 
ing about increased efficiency. 

9. Running cars through from point o/ production to tide-water wiilioui 
trans-shipment, ^Tl\ua has become quite a general practice with ship- 
ments produced east of the Mississippi Biver, and the products of the 
States and Territories west of the Mississippi are rarely trans-shipped 
more than once before reaching tide-water. Grain from Chicago and St 
Louis is shipped all-rail, not only to the principal cities of the Atlantic 
seaboard, but to the points of consumption in the interior of all the Mid- 
dle and New England States. The delays incident to trans-shipment are 
great drawbacks to the effective use of cars, and as well by the saving in 
cost as by the avoidance of these delays has transportation been facili- 
tated and railroad efficiency been increased. 

10. Issuing through hills of lading from Western points of shipment to 
Atlantic and European ports, by making the transportation contracts- 
definite to the distant market, and providing a basis for raising money 
on the shipments, has greatly aided the development of our export trade, 
and thus added to railroad efficiency. It is now customary to ship c^^ain 
and other products from Chicago and other Western trade centres to 
Liverpool, Glasgow and other foreign ports, and the through rate for 
transportation being known, the quotation of foreign markets reg^ularly 
cabled becomes the basis of daily transactions requiring railroad facili- 
liies for their consummation. 

With all the recorded increase in railway efficiency, there is still a 
demand, during every busy season, for more transportation facilities;. 



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381 

from mine and mill, from qnarrj and field, the cry is, " Cars! cars! more 
cars!'* So persistent has been this cry, from every quarter, and pitched 
in every key, that it is not surprising that the railway managers have 
come to mistake the collateral symptoms for the disease. The manu- 
facturer or other producer realizes only that he wants cars In which to 
load his product; its transportation to destination does not so much 
concern him, hence his cry for ''cars." Yet the writer ventures the 
opinion, and not for the first time, that what is needed is not so much 
** more cars " as more movement of cars. 

Freight blockades have been much more common of late than they 
were ten years ago, and they indicate clearly that the cars are in excess 
' of the facilities for their movement, whether of engines, tracks, yards 
or other terminal facilities. 

While the increase of these must continue, the advances most 
needed are ih mechanical details and in methods of administration, 
looking to obtaining a larger average mileage from the freight cars in 
use. 

Just as the reiterated demand for cars leads to the conclusion that 
the building of additional cars will remedy the complaint, so, when 
blockades occur, the railway managers are led to conclude that more 
yard tracks will remedy that evil. It is as if a man with aggravated dys- 
pepsia, finding his system suffering from lack of nutrition, should take 
more food; and then, having his stomach uncomfortably fuU, should 
conclude that he needed more stomach. 

A blockade of freight is a traffic indigestion, and the remedy is not 
in more cars, but in less ; not in more tracks to stand cars on, but in 
less standing cars. When cars are in trains, moving on the main tracks, 
they seem to disappear, and cease to be a cause of embarrassment; and 
in that direction lies the remedy. 

It remains, then, to consider what is needed to apply the remedy and 
make it efficacious. 

In proof of the statement that the greatest defect is in the movement, 
I will adduce the following facts, showing the decrease in their average 
movement that has taken place since 1868 and 1876. The facts in this 
regard are not easily accessible, as many railway companies keep no 
record of freight car mileage; many of those that keep such record make 
no separation of the mileage of their own from that of foreign cars ; 
while but few make any mention of it in their reports. 



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382 

By the ooortesj of the officers of the PeDnsjlvania Company, I am 
enabled to present the following comparison of average miles ran by 
cars owned by that company, they having furnished me with the data 
for the mileage of Pittsburgh, Fort Wayne and Chicago Bailway Com- 
pany cars during the twelve months ending June 80th, 1882, and of their 
Union Line cars in 1876 to 1882, while from a report made by mysdf 
while connected with the Pittsburgh, Fort Wayne and Chicago Bailwaj 
I get the data for 1868. 

MiLBS BUN BT PnTSBUBGH, FOBT WaYMB AND CmCAOO BaUjWAT CaBS. 

During 1868: Average, 14 923 miles. Per secular day, 47.67 
" 1881-'2 " 11806 *' " ** 87.72 



9.95 



Decrease, 21 per cent., 8 117 " " 

This decreased average mileage is in the face of better facilities in an 
important respect for making an increase ; for in 1868 the Pittsburgh, 
Fort Wayne and Chicago cars were not run east of Pittsburgh, while 
since 1870 they have been run to the Atlantic seaboard cities, giving 
them maximum runs of nearly double the length of those of 1868. 

Miles bxtn bt Union Linb Cabs. 



1876 


No. of 


cara 


,8 983. 


Average miles. 


27 811. 


Per secular 


day, 88.85 


1877 






8 800. 








22 668. 




*« 72.42 


1878: 






8 828. 








24 672. 




•• 78.82 


1879, 






4 052. 








24 904. 




" 79.57 


1880 






4 689. 








19 359. 




" 61.85 


1881 






6 843. 








16 788. 




" 53.64 


1882 






6 041. 




for 8 


mo*i 


1 9 858. 




•• 44.82 



These figures show that during 1877, '8 and '9, when the number of 
cars remained nearly stationary, the average mileage did not change 
materially, while with the steady increase in the number of cars from 
1880 to 1882 there is a more than correspondingly decreased average 
mileage. While the number of cars in the years 1879, *80, '81 and *82 
were respectively as 1, 1.16, 1.44 and 1.49, the average of miles run per 
secular day in 1879 bore to that of 1880, '81 and '82, respectively, the 
proportion of 1.29, 1.48 and 1.77 to 1. 

It is not, however, to be inferred that these facts indicate cause and 
eflfect exactly, but they do indicate that from some cause, which most 



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383 

be remediable, the average movement of cars has decreased more rapidly 
than the average number has increased, so that in the case of the Union 
Line the aggregate miles mn in 1879 with 4 052 cars is greater than the 
aggregate movement in 1882 with 6 041 cars, estimating the movement 
in 1882 on the basis of the figures given for eight months, viz. : 

In 1879 4 052 cars made mileage of. 100 911 183 

<< 1882 6 041 ** estimated mileage of 84 752 667 



Increase in cars 2 Oil. Decrease in miles 16 158 466 

** ** 49 per cent. " ** 16 per cent. 
It is claimed by the officers of some of the railroads engaged in the 
movement of these cars that the decreased movement is due mainly to 
two causes, viz. : 

1. The greater extent to which Union Line cars are used in local 
traffic. 

2. The use of the cars in transporting coal and coke westward; 
whereas they formerly ran westward empty. 

That both of these . causes have operated to produce the effect 
referred to cannot be doubted; but they do not and cannot account for 
all, nor nearly all, the decrease. 

In 1868 the mileage of empty cars on the Pittsburgh, Fort Wayne 
and Chicago Railway was but 17.4 per cent, of the total car mileage, 
and in 1881 it had been reduced to 18.2 per cent. ; but in 1868 the local 
traffic of the Pittsburgh, Fort Wayne and Chicago Railway was done 
almost wholly in Pittsburgh, Fort Wayne and Chicago cars, while in 
1881 much of it was done in Union Line and other cars. Yet the average 
miles run by Pittsburgh, Fort Wayne and Chicago cars decreased 
since 1868, as stated, 21 per cent. Again, this decreased movement has 
arisen in the face of greatly increased capacity of locomotives, greatly 
increased average movement of locomotives, and greatly increased 
demand for transportation. To what, then, the great decrease is due, and 
how it is to be remedied, so that the average movement of all freight 
cars shall be,- as it can and should be, at least fifty (50) miles per day, 
and of **line cars," such as the "Union Line," at least seventy-five (75) 
miles per day, is what I propose to show, under the following heads: 

1st. The neoesiity /or more main tracks, which can be met gradually 
by the extension of sidings and the building of sections of additional 
main tracks. This is generally appreciated by the officers of the trans- 



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384 

portatioD departments and receives attention if the financial condition 
of the company admits. 

2d. A need that is more frequently neglected is that of more locomo- 
tives. Of coarse, much more can be done with the existing motiTe 
power of most railroads by adopting the system of running now used on 
the New York Central and Hudson River and Pennsylvania Railroads, 
as hereinbefore detailed, whereby the average miles run by locomo- 
tives can be increased from 30 to 50 per cent But upon many 
railways the number of cars is largely in excess of the motive power 
capacity for their economical movement. A careful investigation of 
the car capacity, as compared with the engine capacity, would show 
that some companies could afford to sell cars and buy engines witii 
the proceeds, for manifestly when cars are in excess they only 
embarrass the movement of such as could otherwise have been 
moved promptly. I remember a case, within my personal knowledge, 
where the general manager of a railroad which had no excess of loco- 
motives, but a deficiency, ordered ten (10) engines and one thousand 
(1 000) freight oars. The capacity of each engine was to haul about 
twenty (20) cars, and if each engine averaged 100 miles per day 
(31 300 miles per annum, which is large mileage for freight engines) 

^, X .1 -x Engine*. MUe«. Cars. 

the aggregate car mileage capacity was jq- X -Jqq^ X 20 — "^ "^ 

., , _ _ Car Miles. Cars. .^ ., - 

car miles per day. Now, ool)00~ "^ 1 000 ~ miles per car per day; so 
that the 10 engines provided for an average movement of 20 miles per 
day for the 1 000 cars. As engines then cost about $10 000 each, and 
cars, say, 3600 each, the money expended was, say, 

For 10 engines at $10 000 each $100 000 

For 1 000 cars at $600 each 600 000 . 

Total $700 000 

Assuming a movement of 50 miles per day as possible and reasonable, 
this amount of money could have been expended to much better 
advantage by the purchase of 

20 engines at $10 000 each $200 000 

800 cars at $600 each 480 000 

Total $680 000 



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385. 

Engines. Miles. Gmrs. 

Then 20 x 100 x 20 = 40 000 car miles per day, 

Car Miles. Cars. 

and 40 000 -f- 800 = 50 miles per car per day, 
whereas in the case cited, if 400 cars were, sufficient to economically 
employ the 10 engines parohased, not only was the expenditure for the 
additional 600 cars a waste, but the cars themselves had to stand around 
on yard tracks and sidings, requiring additional switching engines to 
handle them, and impeding and thereby lessening the possible move- 
ment of the 400. 

3d. The increased movement of cars will require more trains^ which 
will make it necessary for trains to follow more closely. 

On some parts of the Pennsylvania Railroad double trains are run, 
sometimes with two locomotives in front, and sometimes with one at each 
end. It is economical in some respects, but it is open to the radical 
objection of having two persons in control with equal power, with all 
its attendant evils ; and while one may be nominally in command, much 
mischief may be, and often is, done before his designs or intentions can 
be communicated to the other. I do not believe that, on the whole, it is 
economical or desirable. 

What is wanted is : 

(a.) A good automatic signal system, whereby short ** blocks,** oper- 
ated by the trains themselves, may be used for freight trains ; keeping 
them at least one mile apart when running at full speed. 

(h,) A good train brake for freight trains, as nearly automatic as pos- 
sible in its action. 

Such a brake, combined with automatic block signals, would make 
rear collisions absolutely indefensible, and almost impossible. 

4th. The making up of trains at the point where cars are loaded, and at 
the terminal stations where cars are received from other railroads, ib 
capable of being greatly improved. At all such points the cars, aB 
brought into the train yard, should be so thoroughly assorted and classi- 
fied but that one ** shift " would be needed to separate all the cars for any 
one destination from the others. The rale is rather, so far as the writer s 
observation goes, that the cars are made up into trains just as they com. 
into the train yard, and the train has to be ** shifted over*' at every sno- 



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386 

oesaiTe ** train yard *' to detach the cars that belong there or that go 
thence by local train. 

Designating the destination of cars by the letters A, B, C, etc., com- 
pare two trains of twenty cars each, made up as follows : 

1. A, Ay By A, C, A, B, B, C, A 0, A, A, C, A, B, D, D, C, D. 

2. A, A, A, A, A, A, A, B, B, B, B, (7, C, C, C, C, D, D, D, D, 

The first indicates such a train as osnally made up ; the second repre- 
sents the same train made up to facilitate movement This improre* 
ment is perfectly feasible, and, if strictly followed, would greatly facili- 
tate the movement of trains, and therefore increase the movement of 
cars. 

5th. The detention qf cars at staiinns and private sidings is a promi- 
nent cause of the small average car movement. It can only be remedied 
by a reasonable but adeqnate ''demurrage'* charge. The charge of $5 
per day, set forth as a penalty for car detention on many railroads, is so 
manifestly unreasonable as to defeat itself ; it is so seldom that it is ac- 
tually collected. In this, as in other infractions of law, it is the certainty 
and not the severity of the penalty that tends to prevent the violation. 

Low rates of transportation, coupled by contract with invariable 
charges for demurrage, reasonable in amount, but certain in collection, 
will solve this difficulty, and no other remedy known to the writer will 
effect its correction. 

6th. It is probable that the greatest loss from the non-movement of 
cars results from their absence on foreign railroads. Not only do many 
railway officials allow *' foreign cars ** to be used systematically in their 
local traffic, but they allow them to stand on sidings and in yards, and 
do no good to any one. A coal company owning 100 cars recently found 
but 42 of them in its own trade ; the remaining 58 had been absent from 
a week to two months, and one was found in a furnace yard loaded with 
ore placed on it nine weeks before I An investigation made by the writer 
in 1869 showed that the cars of the Pittsburgh, Fort Wayne and Chicago 
Railway absent on other raiboads in March and October, 1868, had made 
an average mileage, while so absent, of 20]Vd miles per day, for which 
the Pittsburgh, Fort Wayne and Chicago Railway Company then re- 
ceived li cents per mile, or the munificent sum of 30i^ cents per car 
per day. The rate of '' car mileage " has been sinc^ reduced, first to one 



Digitized by VjOOQIC 



387 

cent, and then to three-fonrths of a cent per mile ran, so that on the 
present basis the company would reoeiye for similar mileage 15iS'o cents 
per car per day. As mj statements show a generally decreased move- 
ment of cars, it is not likely that the present average movement, when on 
foreign railroads, equals that found for 1868. 

The only effective way to bring about a prompt return of oars to the 
railroad of the company owning them, is to make it the interest of the 
foreign company having them to return them to their owner, which it 
manifestly is not under present regulations. 

This can best be effected by aper diem charge /or cars when onfm^eign 
road9. 

This idea is not new, and the writer does not claim it as his discovery; 
it has been repeatedly discussed by railroad conventions, and they have 
decided against it— not on the ground of its inherent injustice, or of any 
difficulty in its application, but simply because of the conservatism of the 
railway managers, and a lurking fear that if all did not adopt it, those 
that did would be discriminated against, in favor of the lines that adhered 
to the old system. That its adoption by a leading line, like the Pennsyl- 
vania, would result in much more than compensating advantages, I have 
no doubt, and that it would be speedily followed by other lines I feel 
as little uncertainty ; while its adoption by the *'Trank Lines" is per- 
fectly feasible, and would be a success from the outset, greatly to their 
advantage. 

There is no other business that I know of in which the use of millions 
of dollars worth of property is entrusted by the owners to others, with 
liberty to use it as much or as little as they choose, to pay for its posses- 
sion only on the basis of its actual use, and to account for its use without 
check or record being kept by its owners ; yet such is the case with the 
interchange of freight cars. One of the advantages of this proposed basis 
of settlement for *' car service" is the facility with which the accounts 
can be kept. Every junction or intersection becomes a * * clearing house " 
where is kept the number of cars received from and delivered to the con- 
necting road each day, and the balance, added to or deducted from the 
previous day's balance, gives the number of cars with which the connect- 
ing road is to be debited or credited for the day, at the ** per diem " rate. 
It will probably be conceded by most railway officers that the '*per 
diem '* basis is the most equitable, but the important question arises — 
what shall be the rate ? To this I unhesitatingly answer, the rate should 



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388 

be fixed from time to time, perhaps every 2, 3 or 5 years, on the basis of 
the average economic value of the cars in use to their owners. 

By ** average economic value," I mean the average capacity of cars 
to make "net earnings " when properly handled, there being no reason 
apparent to me why the owner of a car should let another use it for less 
than its value to its owner. 

It must be apparent that this value will vary from time to time with 
the varying circumstances, such as : 

1. Average capacity of cars. 

2. Average rates obtainable for traffic as compared with its cost 

3. Average movement of cars. 

To the question, what is the present ** economic value** of the aver- 
age cars in use, I reply as follows, viz. : 

Taking the actual traffic, mileage and earnings of the most prominent 
parts of the Pennsylvania Bailroad Company*s system for 18B1, and as- 
suming the average miles run by cars on the three lines to be 87 J per day 
(approximately that of the Pitsburgh, Fort Wayne and Chicago Railway), 
the value of each car per day will be shown in its average daily net earn- 
ings as follows : 



I 



1881. 



Penn. R. R. 



I P.. F.W.&C. 



Loaded car mileage 216 572 441 

Empty *' ♦• 108 608 166 



C. &S. 

By. 



I 



Total *• '* 

Total ton -mileage 

* Average tons per car 



98 096 632 j 37 292 500 
15 969 647 ' 6 165 648 



114 066 279 

1 044 447 161 

tons 



9iVa 



43 458 148 
401 946 112 
tons 9A»5 



1 . 325 180 607 

2. 2 655 438 764 
3 tons 8^oV 

Net earnings per ton per mile 4. | cents ^\fQ*u | cents ^^^q cents -f^^ 

I I 

- car " " 5. cents 2^^%^ , cents 2/o»o c«nts 2iVo*o 

Average miles ♦' •♦ ♦* day 6. Estd. 37i Estd. 37J Estd. 37i 

Net earnings •' *• " ** 7.; $1.11 



TOO 



$1.10 



$0.76 



Average of three railroads 99 cents. 

* This average differs from that shown in the company's reports, being an average for all 
cars run, loaded and empty, while the average load reported by the companies is of the loaded 
cars only. 



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389 

The mnob greater traffic of the Pennsylvania Bailroad and Pittsburgh, 
Fort Wayne and Chicago Railway would make the actual average over 
$1 per car per day, even on the low average movement of 371 miles per 
car per day, and with the low average tonnage per car. 

When we consider the present average car capacity as at least 15 
tons, and on say 75 per cent, of loaded mileage, with an estimated 
movement of 37 ^ miles per day, and net earnings of ^ cents per ton 
per mile, we would have as the economic value of each car per day. 

Tons. Avenge Tons. Average Miles. Cents. 

15 X I'jh = llj2o%, which X 37i X A = 31.26,^0. The 

** economic value " of an average freight car is probably between $1 and 
$1.25 per day under existing circumstances, and we will be justified in 
assuming that $1 per day would be as low a rate as could reasonably be 
fixed as a charge for demurrage, and for the use of cars when on foreign 
roads. 

It will be objected to this rate that it amounts to $26 prer car per 
month, which is much more than a fair interest on the cost of a car, plus 
the cost of maintenance, and that cars can be hired for $15 per month. 
To this I reply that — 

1. Cars cannot be hired for $15 per month, to be returned the 
next day, next week, or at the pleasure of the party hiring them, as 
foreign cars are returned. 

2. The interest on cost, plus the cost of maintenance, Ib no proper 
criterion. 

A company having cars, when cars are in demand, does not wish and 
should not be obliged to provide cars on this basis for its less provident 
neighbors. If A. has wheat, when wheat is in demand, and he can get 
$1.50 per bushel, it is no answer to his demand for that price for B. to 
say that it cost but 50 cents per bushel to grow it, or that he can get all 
he wants next season for 75 cents per bushel. 

The company that has providently secured an adequate supply of 
cars is entitled to their use or its value. 

It may be further objected, that railway companies will not take cars 
from other companies on the basis of paying for their use all that they 
could earn net. 

To this I reply— 

1. That the average mileage upon which the rate of $1 . 00 per day is 
based, is low and can easily be greatly exceeded, by prompt handling, 



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390 

except in oases where the terminal road has a very short hanl, and HuA 
the primary object to be secured is prompt handling and quick return 
of cars. 

2. In cases where terminal roads have short hauls, they can best be 
compensated by a terminal charge, which is now done universally (as I 
understand) at New York. It will be necessary, in the near future, and 
will certainly be more equitable, to allow terminaLs in all cases where 
traffic passes over two or more railroads. 

To the further question, whether I propose that the owners of 
private cars be compensated for their use upon the same basis, I would 
answer— Yes I so far as the principle of a per diem rate is conoezned, 
and No I in regard to the rate itself. The governing circumslwnoes are 
so different, that one-half the rate per day allowed for the use of foreign 
railroad companies* cars would probably be fairly equitable. 

The adoption of the per diem rate will ** pay " any company whose 
traffic is large and whose lines are scattered over as large a district as is 
covered by most of the leading systems, and that it will tend to increase 
the movement of freight cars is very apparent. 

The president of a prominent railroad said to the writer over a year 
since, that the more cars they got the less mileage they averaged, and 
that the only consolation he had was that his neighbors did not **do so 
well'' as he did. I think he should have said that his neighbors ''did 
worse,'* than he, as neither of them could be said, in the light of the 
above facts, to have " done well." 

This is consolation that does not console ! 

It must not be inferred that because I have made my statements 
from, and based my arguments on, the traffic and car movement of the 
Pennsylvania and Pittsburgh, Fort Wayne and Chicago Railway, and the 
Union Line, that their record is worse than that of other leading rail- 
ways ; on the contrary, I believe it to be equal to the best, and better 
than that of most of the railroads of the country ; their facilities are cer- 
tainly superior to most of their competitors, and their administration is 
certainly equal to any. 

If, then, these things be true of the best of our railway lines, what 
must be the facts upon those less advanced in facilities and admlmstra- 
tion? It would certainly justify my postulate, that "what is wanted 
is not more cars, but more movement of ctirs. '* 



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891 



SOHEDULE A. 

Statement showing Beoeipts of Qxain at New York by Canal and Bail, 
1871 to 1880, and at other ports by Bail, 1875 to 1880.« 





At Naw Yobk. 


At 
Boston. 


AtPhlla- 
delphla. 


At BalU. 
more. 


Total 


Taiits. 


ByOaniO. 


By BftiL 


Total 


byBaU 




BushelB. 


BushelB. 


Bashels. 


Bushels. 


Bushels. 


Bashels. 


Bushels. 


1871 


62 527 498 


84 OBI 880 


86 649 828 










1872 


60 724 027 


87 686167 


88 810 194 










1878 


|48 496 920 


46 667 670 


89 063 490 










1874 


46 470 261 


66 887 678 


101827 884 










1876 


87 867 866 


64 069100 


91946 986 


18 821063 


22 462400 


22 048 669 


116 911 182 


1876 


82 786 778 


69 047 963 


96 949 262 


22 768 698 


36 810 666 


36 186 276 


168 297 492 


1877 


48 366176 


60 892 967 


108 818 782 


23 216 467 


26 420 646 


86 846 470 


184 876 489 


1878 


68 906 872 


86 860 079 


162 862 170 


27 291 781 


46 474 660 


47 076 240 


206 191 760 


1879 


67 044 406 


101929 243 


168 973 649| 


32 600 829 


47 398 466 


66 799 926 


248 628 468 


1880 


71089 816 


96 414 822 


I666O4637I 


37 091004 


49102 688 


60 920 813 


242 629 827 



* From Beport on Internal Oommerce of United States for I88O1 pages 160 and 184. 



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392 



SCHEDULE B. 

Statement of Comparative "Tonnage Mileage," or Tons carried one 
mile, on New York State Canals, New York Central and Hndson 
Biver Railroad, New York, Lake Erie and Western Bailwaj, and 
Pennsylvania Railroad, from 1860 to 1881 inolnsive. 



Yeabs. 



Canaln. River RR. Railway. Railroad, t 



1860 809524596 * 199 231 392 

1861 863 623 507 237 397 974 

1862 1123548430 '296963492 

1863 1034130023 312 195 796 

1864 871335160 314 081410 

1865 843915779 264 993 626 

1866 1012448034 ' 381075 647 

1867 958362953 t *362180606 

1868 1033751268 455 046 715 

1869 919153611 589 362 849 

1870 904 351572 , 769 087 777 

1871 1050104125 888 327 865 

1872 j 1048 575 911 1020 908 885 

1878 1057711089 1246 650 063 

1874 ' 938774141 1391560 707 

1876 ' 727597364 ' 1404 008 029 

1876 570969064 ' 1664 447 055 

1877 1 857305563 1619 948 685 

1878 ' 937789464 2 042 756132 

1879 1 962 908 600 2 295 827 387 

1880 ' 1223 699 087 2 525139 145 

1881 1 t 503 498 886 2 646 814 098 



214 084 395 

251 350 127 

351092 285 

403 870 861 

422 013 ^ 

388 657 213 

478 486 772 

549 888 422 

595 699 226 

817 829 190 

898 862 718 

897 446 728 

950 708 902 

1032 986 809 

1 047 420 238 

1 016 618 060 

1 040 421 921 

1114 586 220 

1 224 764 438 

1 569 222 417 

1 721 112 096 

1 984 394 866 



214 162 018 

280 262 533 

376 196 127 

393 746 268 

420 627 223 

420 060 360 

613102181 

565 667 813 

676 776 660 

1 927 714 166 

1 014 662 970 

1 244 328 216 

1622 029 044 

1 870 637 68T 

1 916 726 M3 

2 026 228 116 
2 221 693 427 
2 086 669 4% 
2 368 330 428 

2 974 926 881 
3239 482 798 

3 631 829 469 



* From 1860 to 1867, New York Central only. 

t Eastward traffic only. 

t Includes Branches and P. and E. and, after 1871, United Railways of New Jersey. 



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393 



SCHEDULE 0. 
Statement showing Popolation and Miles of Bailroad in States and 
Territories, in three groups, tributary to the three lines of Bailroad 
whose ton-mileage has been given, for the years 1860, 1870 and 1880. 





POFUIATIOM. 




New York 


1860. 
3 880 735 

672 035 
2 906 215 


1870. 
4 382 759 

906 096 
3 521 951 


1880. 
5 083 810 
1130 983 
4 282 786 


1870. 

3 928 
1125 

4 656 


1880. 
6 019 


New Jersey 


1 701 


Pennsylvania 


6 243 


Total-3 States... 


7 458 985 


8 810 806 


10 497 679 

1 


9 709 


13 963 


Ohio 


2 339 511 

1 350 428 

1 711 951 

749 183 

775 881 


2 665 260 
1680 637 
2 539 891 
1 184 059 
1054 670 


3 198 239 ! 
1 978 362 
3 078 769 
1 636 331 1 
1 315 480 1 


3 538 KQ1Q 


Indiana 


3 177 

4 823 
1 638 


4 454 


Illinois 


7 955 


Michigan 


3 Qai 


Wisconsin 


1 
1 525 1 « i?»n 




14 701 




Total-5 States . . 


6 926 954 


1 
9 124 517 11 207 181 

i 


25 382 



Iowa 

Minnesota.. 
Nebraska . . 

Kansas 

Missouri . . . 
Colorado . . 

Dakota 

Wyoming.. 
Idaho. . . . . 

Utah 

Montana... 



T^t^i J 6 States. . . ) 
T^**M 5 Territ'es f 



Total 



U4 

15' 



States.. I 
Territ'es ( 



Total of U.S. 



674 913 

172 023 

28 841 

107 206 

1 182 012 

34 277 

4 837 



40 273 



1 194 020 

439 706 

122 993 

364 399 

1 721 295 

39 864 

14 181 

9 118 

14 999 

86 786 

20 595 



1 624 620 
780 806 
152 433 
995 966 

2 168 804 
194 649 
135 180 

20 788 

32 611 

143 906 

39 157 



2 244 382 I 4 027 950 I 6 288 920 



16 630 321 21 963 279 27 993 680. 



31 443 321 38 558 371 50 152 866 



2683 
1092 

705 
1501 
2000 

157 
65 

429 



257 



8 889 



33 299 



52 914 



5235 
3 108 
2000 

3 439 

4 011 
1531 
1265 

472 

220 

770 

48 



22 099 



61444 



93 671 



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394 



SCHEDULE D. 

Statement of Steel Bails Mannfactnred in and Imported into the United 
States to December 81, 1881. In tons of 2 000 pounds. 

From Report of James M. Swank, Seoretary Iron and Steel AflsocUtion. 







Tons Imported. 

* 


Totals. 




Open Hearth 
SteeL 


Bessemer 
I Steel. 

[ 2660 

7226 

9660 

34 000 

38 260 

94 070 

129 016 

144 944 

290 863 

412 461 
I 

432169 

660 398 

683 964 

964 460 

1330 302 


• A"*~^ 


1867 




9 897 
9149 
18 616 
26 217 


149 786 
169 671 
100 616 
18 274 

36 

10 

26 067 

168 230 

249 309 


2660 


1868 


7226 


1869 

1870 

1871 


9660 

34 000 

1 38260 


1872 


1 243866 


1873 


288 686 


1874 


245 469 


1876 


309137 


1876 


413 461 


1877 


432 204 


1878 


509 806 


1879 


718 170 


1880 


1126 306 


1881 


1 604 828 






Totals 


67 378 


6 114 321 


860 787 


6027 486 







* Prior to 1872. steel rails imported were reported as iron. 



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396 



SCHEDULE E. 

Statement of Average Miles run by Freight Locomotiyes, and average 
number of Tons Freight hauled one mile by each Freight Locomo- 
tive on Pennsylvania Bailroad, from 1870 to 1881. 





AYBJUOKBd 

Pennsyl- 

yanla B. R. 

Division. 


[IZJESRXTKBT 

United N. J. 
Bailroads. 


FrriohtLoc 


OMOXrVKS. 1 

1 


AvKRAQK Tons Hauled Owe Mhjb 
PKB Locosconvx— IN Mnjjom. 


^KARS 


Phil, k Erie Average on 

B. B. 1 lUl 
Division. 1 Divisions. ! 


P. B. B,U. B. R. 
of 
Div. N.J. 


P. iE. 
Div. 


td 


1870 


19 888 




16 786 19 244 :; 2.2 




1.9 


2.1 


1871 


22 422 




18 860 21709 , 2.6 




2.8 


2.6 


1872 


22 668 


23 077 


21607 22 828 j. 2.6 
18 744 22 225 1 2.7 


2.1 


2 6 


2.6 


1878 


24 497 


17 809 


1.6 


2.8 


2.4 


1874 


22 268 


17 716 


16 781 20 874 2.7 


1.7 


2.4 


2.5 


1875 


23 224 


16 964 


14 878 20 498 ;. 2.9 


1.6 


2.6 


2.6 


1876 


24 600 


•17 194 


15 205 21716 , 3.2 


1.8 


2.7 


2.9 


1877 


20 610 


18 768 


14 066 19 245 || 2.8 


2.0 


2.6 


2.7 


1878 


20 299 


18 960 


, 19 502 . 20 000 ' 8.1 


2.0 


8.9 


8.0 


1879 


26240 


21990 


' 22 705 


24 866 1; 4.8 


2.8 


6.8 


4.2 


1880 


1 26107 


23 876 


22 280 


26 097 l' 4.9 

. 1 


8.1 


6.8 


4.6 


18^ 


29 297 

1 


28 259 


' 18 747 


27 644 


5.4 


8.9 


5.0 


ff.l 



System of running locomotives " first in, first out," adopted in 1878 
—full eflfect first shown in 1879. 



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396 



SCHEDULE F. 
Statement showing Length of Roads and Gross Earnings in 1881 of 
Thirteen Systems of Bailroads. 



Miles. 



GBOfiS EABKING8. 



New York Central * HudBon River , W3 j i $29 322 683 

Lifcke Shore & Michigmn Southern 1 177 | , 17 880 000 



Can»dft Son them. . 
Michigan Central. 



3309 259 
8800 486 



; I I 
Total New York Central System , ' 3 623 I 

New York, I^ke Erie & Western 1020 j 

t I 

Pennsylvania Eastern System 3041 I ^ $44224 716 



Western System | 2 529 

TotAl Pennsylvania System ' 



, lO/o^^ 



Total, Three Trunk Linea 

Wabash, St. Louis & Pacific | 

Chicago, Burlington k Qulncy 

Chicago, Bock Island & Pacific | 

Illinois Central Northern j 1 320 

Chicago, St. Louis k New Orleans Southern . . . . j* 671 



31 058 790 



6 570 



10113 2lj«,.V 

3348 , 

3160 



I' 



1336 



$6 733 964 > 
4 059 151 ! 



Chicago & North- Western 

Chicago. Milwaukee k St. Paul. 
Missouri Pacific 



1891 
8 276 

4 260 



$50 373 277 
20 715 605 



75 283 006 

$165 371383 
14 467 790 
21 176 456 
11956 907 



10 793 106 
19 334 072 

17 026 461 



1012' $8 640 967 I 

* I 1 , I 

Leased and controlled lines * 778 | 1*087 484 , 

1 ^ 5 785^ 1 

Louisville k NaahvlUe Eailroad, and Lines I ' 

owned by 1*^ |/ 



$10 911650 



Lines leased, &c 

Louisville, Cincinnati k Lexington. . 
Nashville, Chattanooga & St. Louis. 
Georgia Ballroad syntdm 



434 ) 

272 ' 1196112 1 

521 ' I 2256186 | 

641 ' ' 2643032 | 

1 3 034 — , 1 



UnlonPaclflc, proper | 1821 | ,$24258817^ 

Lines m interest , 2449 \ , 7 608 936. 



4 270 



Central Pacific. 



2 874 ! $24 094 101 I 



Southern 



Pacific I 1281 



3 435 946 ; 



4156 



Total Thirteen Systems.. 



Total of United States In 1881, of which 
Earnings reported 



Proportion Thirteen Systems bear to Whole. 



44 627 miles. 



16 906 980 



31 867 753 



27 630 046 



$364 168 398 



94 486 mUes. 



$726 325 119 



«tV. ^ 



48A&V 



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AMERICAN SOCIETY OF CIVIL ENGINEERS. 

INSTITUTED 185 2. 



TRAJSiS AMOTIONS. 

Non.— This Society is not responsible, as a body, for the facts and opinions advanced in any 

of its publications. 



CCXIilX, 

(Vol. XL— November, 1883.) 

RAPID METHODS IN TOPOGRAPHICAL SURVEYING. 

By WiiiiiiAM Bell Dawson, C. K 
Bead September 20th, 1882. 



The object of the survey referred to in the present paper was to pre- 
pare a map, to the scale of 2 inches to the mile, of a portion of the 
gold-field lying along the Atlantic coast of the Province of Nova Scotia, 
together with plans of the mining districts to the scale of 500 feet to 
the inch. The region consists of a series of slaty rocks set on edge and 
mnning east and west ; while the direction of all the principal streams 
and longer lakes is^ north and south. This makes the topography com- 
plicated and the amount of detail very g^eat. Lakes are numerous ; 
and the ground is hilly between them, although it rarely rises to a height 
of more than 300 or 400 feet above sea-level. The river valleys are 
usually wooded ; and in many places the streams form long and narrow 
pools, which wind through swampy thickets of willow and alder. These 
are known as " still waters." The uplands consist of rocky ridges and 
masses of loose rock, mostly overgrown with scrub and thickets. The 
lakes seldom have any beach, but are sometimes surrounded by peaty 
swamps, and sometimes by shores of loose rock. There are settlements 
in places and a few mining villages. Two lines of road run through the 
region surveyed, one along the shore and the other further inland, par- 
allel to it ; and there are a few cross-roads. The only map which existed 
was to the scale of li miles to the inch, showing the roads, with the 
houses along them, with tolerable correctness. The principal lakes and 
streams were sketched in their position relatively to the roads, without 
any attempt at accuracy in detail ; and some of the more prominent 
hills were indicated. 



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398 

The use of the ohaiii in the survey of a country of this nature would 
have involved the expenditure of an amount of time altogether uDJnsti- 
ilable. It was therefore decided to employ stadia hairs and the Bochon 
micrometer telescope for the measurement of distances, as the only prac- 
ticable methods under the circumstances. By taking advantage of the 
directions of the roads and principal streams, it was possible to divide 
the region into a network of quadrilaterals, with sides of about 2 
miles in length. Along these sides the main lines of traverse were ran ; 
and a thorough check on the work was thus obtained. These traverseB 
were afterwards worked out by latitude and departure, to fix the posi- 
tions of all the principal points. 

The instrument principally employed was a 6-inch transit theodo- 
lite, American pattern, with a vertical circle and 4i-inch compass needle. 
It was fitted with stadia hairs, and used with a Sopwith leveling-rod of 
3 draws. The telescope was of 8i inches focal length, with an erect- 
ing eye-piece magnifying 19 diameters ; an,d the stadia hairs consisted 
of 3 horizontal spider lines, unequally spaced, the larger interval 
being calculated to correspond to 100 feet of distance for each foot in- 
tercepted on the rod. Practically, this larger interval was almost ex- 
clusively used. The smaller one was intended for longer sights, and 
often proved useful when the rod was partly obscured by intervening 
objects. In using the instrument the central horizontal hair was set 
at an even foot on the rod, and the reading on one of the outer hairs 
observed. In this way the levels were readily carried along with the 
work when desired, it being only necessary to note the reading on the 
vertical circle. From an optical point of view it would have been pref- 
erable to take t)ie readings on 2 hairs equally distant from the axis 
of the telescope, as the central and outer hairs were not always equally 
distinct. This would best be avoided by having lenses in the telescope 
which would give a perfectly fiat field, as the use of the outer hairs 
would entail additional trouble in reducing the levels, or a still more 
serious loss of time in taking a third reading on the central hair when 
levels were required. With spider lines, the vertical hair is necessarily 
thrown out of the plane of the others by the amount of their thickness, 
which prevents their being brought into focus at the same time. In 
damp weather they were also found to become slack and wavy occasion- 
ally, which was fatal to accuracy and involved a loss of time. These 
inconveniences would be avoided by the use of lines ruled on a glass 
diaphragm. 

The angular values of the spaces between the horizontal hairs were 



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399 

determined by direct measnrement The instrnment was set up on a 
level piece of ground, and the distance of the anterior focus of the 
telescope from the centre of the instrument (18 inches) was first meas- 
ured on the ground from the plumb-bob. From this as a zero point a 
line was carefully chained, and observations taken on the rod from 100 
to I 400 feet along it. In this way, the readings obtained were propor- 
tional to the distance from the zero point, within the limits of observa- 
tion ; and the average of all gave a very dose and satisifactory value as a 
basis for the calculation of tables. With this as a datum, the distances 
of the rod from the anterior focus, corresponding to a few leading values 
of the length intercepted on it between the hairs, were first calculated ; 
and the intermediate distances, for every 100th of a foot between 0.30 
of a foot and 14 feet, found by interpolation. It was then only neces- 
sary to add a constant value (13 inches) to each to have the true distances 
from the centre of the instrument ready to enter in the tables. A sup- 
plementary table containing the percentage to be deducted for slopes up 
to 10^ was also prepared. It was not thought necessary to combine this 
with the other table ; and in practice slopes up to 2^ were neglected in 
reducing for horizontal distance except on long sights. 

The micrometer telescope was a double refracting one on Bochon's 
principle, with a vernier reading to seconds, and a range from to 45 
minutes. It was used with a pair of discs set 8 feet apart. To test its 
accuracy, a line was carefully chained of over a mile in length along a 
straight portion of railway track, and a double series of observations 
taken on it. These showed that the index error varied along the instru- 
ment in an approximately constant ratio. A graphic method was made 
use of to average the results of the individual observations ; the correc- 
tion at each point was thus obtained, and applied to the true values of 
the angle subtended by the discs within the limits of distance at which 
it was intended to use the instrument. 

The methods employed enabled the party in the field to be reduced 
much below the usual numbers. The authc> found that with the assist- 
ance of Mr. H. Archbald, Jr., and one or two men, according to circum- 
stances, the work could be efficiently carried on. In all the ordinary 
traversing the theodolite and leveling rod were employed. Both on 
roads and in following streams it was found more expeditious to take 
sights of 200 to 400 feet, than to spend time in clearing longer sight 
lines. The instrument and rod were moved forward alternately as in 
leveling, and it was found sufficiently accurate to read the bearing 
directly on the end of the compass-needle to the nearest i degree. 



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400 

The 9ame end of the needle was used thronghont the work, and by it 
the infltrtiment was also set in detennining the magnetic variation, ^hich 
was done at several points in the region surveyed. The instramental 
error was thus eliminated as far as possible. The roads, as a rule, were 
not more than 25 feet wide, and wooded along the sides, and at every 
bend the view was intercepted ; while at places the ootintry was more 
open, and several intermediate sights oonld be taken. As a back-sight 
and fore-sight were taken from each station, the number of sets-xip to 
the mile was usually 8 to 10 ; and without levels or intermediate 
sights the rate of advance was nearly a mile an hour. In road- work, 
which required the most care, 8 to 4 miles could easily be done in 
a day, including levels. In traversing a stream, points in its bed were 
chosen when practicable, as the line of the stream itself was usually the 
most open ; and much cutting was also avoided by sighting across the 
ponds met with on its course. The g^eat advantage of stadia measare- 
ments over chainage was here very obvious. A length of li to 2 miles 
of this class of work could be done in a day. The smaUer lakes, under 
i of a mile long, were also surveyed by stadia measurements when 
it was possible to walk round them ; otherwise, their shape was deter- 
mined by bearings from two points on the traverse to any prominent 
trees or other objects on the opposite shore. On the traverses of 
secondary importance, a prismatic compass and ranging-pole were tried, 
distances being taped. This was found expeditious in the denser 
thickets, as much less cutting was required on the sight lines ; but 
when still waters or small lakes were met with, a corresponding amount 
of time was lost as compared with stadia measurements. The form of 
note-book used in the stadia work is shown below : 



Stalion. 


Bearing. 


Beading. 


Haira. 


Vertical, i DlBtance. 


1399 on (to)... 


N. 68" 30' W. 


8.00 
8.78 


Large. 


— r 01' 


on (X) 


N. 78''45'E.. 


3.00 
5.74 


Large. 


+ r 18' 


1400 on («).... 


S. 58'* 30' W.. 


6.00 
9.35 


Large. 


+ 0M2' , 


on (.V).. . 


S. 83° 45' E.. 


6.00 
8.45 


Large. 


+ 2"' 34' 




1401 on(y).... 


S. 86'' 30' W.. 


4.00 
6.26 


Large. 


— r 29' 




on (2).... 


N. 54'' 15' E.. 


3.00 
8.62 


Large. 


-f- O** 02' 1 








^ - 




^ _ ^ 



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401 

On the page opposite, a sketch of the traverse was made, with the 
t-opography on either side, and notes of the character of the country. 

An aneroid for the measurement of levels would have been of little 
service. Levels were of most importance in the vicinity of lines of 
watershed, to show to which basins the various lakes met with belong, 
and the probable outfall of a lake as indicated by the levels of the 
streams crossed in approaching it. Differences of level under 10 feet 
were of the most consequence. A contoured map was not contemplated ; 
but the relief of the country is indicated by lines of hill-marking, each 
of which corresponds approximately to a rise of 50 feet. It was not, 
therefore, necessary to make the levels continuous over the whole region. 
In the extent of each of the mining districts of which plans were to be 
made, the levels were connected, in order to indicate the amount of 
head for milling purposes afforded by the various lakes. The levels 
were reduced from the fore and back sights, and the reading on the 
vertical circle as found in the field notes. For this the following form 
was used : 



Sight. 



DlRtance 



1399 on {w) ! 95 

on (x) 332 

1400 on (x) 164 

on (y) 297 

1401 on (y) 274 

on (z) I 680 



Vertical. 


Back 
Sight. 


— r or 


8.00 


-f-r 18' 





-f-O*" 12' 


6.00 


-f-2'»34' 




- r 29' 


4.00 


-f-0^02' 





Fore 


Slopb Sight. 


Sight. 


Bise. 


Van. 





1.6 




3.00 


1 7.5 


0.6 


6.00 


13.3 
7.1 




3.00 


' 0.4 





In surveying the larger lakes, the theodolite was set up in a com- 
manding position and adjusted in azimuth till the vernier and compass 
needle were simultaneously at zero, and the micrometer telescope was 
placed beside it on a light tripod. The assistant went round the shore 
of the lake in a boat, and held the staff bearing the discs vertically at all 
important points, giving finally a turning point at which he remained 
while the boat returned to take the instruments on to their next position. 
From this a back sight was taken on the turning point, and intermediate 
sights as before^ till the next turning point was reached. The bearings 
were read on the vernier to the nearest 5 minutes, aa this corresponds 
with the limit of accuracy with which the instrument could be set in the 



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402 

magnetic meridian. The diurnal variation, of which the extreme valne 
was -f- 4 minutes, was also neglected as a mle, although it was sometimes 
taken into account in comparing the results of the latitude and de- 
parture calculations. In taking observations for the magnetic variations, 
a time of day was chosen at which the needle was at its mean position ; 
and observations on days of magnetic storms were thrown out 

The sights taken with the micrometer telescope ranged from 600 to 
6 000 feet. Although reading to seconds, it was found impracticable to 
discern differences of less than 5 seconds of angular value, except under 
unusually favorable circumstances. The sights on the turning points 
formed a connected traverse, and their length was kept as much as pos- 
sible between the limits of 1 000 and 2 500 feet At 1 000 feet a difference 
of 5 seconds corresponds to 3 feet in the length of the sight, and at 
2 500 feet, to 18 feet ; which latter in the plotting is but the I50th of an 
inch. The atmospheric refraction being unequal in the case of the two 
discs was a source of error, especially in the longer sights. Its amount 
was not determined, although in certain states of the atmosphere it was 
quite perceptible. This could, however, be avoided by holding the disc 
staff horizontally. 

The micrometer telescope presented several important advantages. 
When landing from the boat was difficult, as was usually the case, owing 
to the rocky character of the lake shores, the staff was held on the edge 
of the boat ; and although the waves communicated a slight vertical 
motion to it, this caused no inconvenience in taking the observation, as 
the images of the discs moved together just as they would if viewed 
through a sextant. At the turning points a landing was essential ; but a 
considerable amount of time was saved by avoiding it at the intermediate 
points. The telescope being laid freely in a trough-shaped support on 
its tripod could be rotated axially, making the images of the discs pass 
horizontally over each other, which enabled their coincidence to be de- 
termined with precision. On the other hand, some light was lost in 
passing through the double refracting prism, which was a source of in- 
convenience in dull weather. On short sights the largeness of the 
angle and consequent obliquity of the light from the two discs made the 
images indistinct ; but this was largely compensated by the fact that an 
angular difference was of less importance as compared with the length of 
the sight On sights under 600 feet, the angle had to be measured on 
the vertical circle, unless the rod was at hand ; the distance obtained in 
this way was uncertain within 2 per cent. For these reasons, sights 
under 1 000 feet were avcMded on the through traverse. The form of 



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408 

note-book used for the lake surveys was the same as before, the reading 
on the micrometer telescope being entered in the third column. On the 
opposite page a diagram of the sights taken was kept, and a note-book 
was also kept by the assistant in which the form of the coast line between 
the points sighted on was sketched. 

A lake of moderately regular shape 3 miles in length could be siir- 
yeyed in 2 days. Where arms and islands were numerous, the 
time was proportionately longer. A considerable amount of skill was 
called for in the choice of stations, and in taking advantage of the direc- 
tion of the light and character of the weather. 

The principal summits around the lakes could be readily fixed in 
position and altitude by bearings and vertical angles from any two 
stations. Any prominent tree or rock that could be kept in view served 
for this purpose. The intervening hills were sketched. 

Much thought was bestowed by the writer to devise a plan by which 
the instruments for such surveys as these could be combined into one. 
A micrometer telescope mounted with horizontal and vertical circles 
would not serve even for lake work alone, as it would not be suitable for 
taking bearing^, and its length would make the instrument unsteady in 
windy weather. An instrument of the character of the omnimeter, re- 
quiring a separate reading on each of the discs, would take up more 
time than the micrometer telescope, and would lose its principal 
advantages ; it would also be much too cumbrous in its manipulation for 
ordinary traversing. A telescope with a divided object-glass, on the 
principle of those used in astronomical observatories for measuring the 
sun*s diameter, if mounted on a theodolite st-and, might be made to 
serve all purposes. In order to secure the advantages already referred 
to, it would require to be capable of being rotated azially ; and it could 
also be fitted with stadia lines. The practical disadvantage of such an 
instrument would be its complication, and the number of delicate parts 
which would be exposed to injury. For work of so varied a character 
as that referred to, the most serviceable instrument is an ordinary 
theodolite, adapted for stadia measurements, and combining lightness 
with strength in its coustruction. 4 or 5 inch circles reading to minutes 
would be sufficient ; and both circles should be covered, or protected by 
guards, as otherwise they soon become illegible. The compass box 
should be circuUr, and the needle not less than 4 inches in length. 
Illumination for the cross-hairs and a diagonal eye-piece are also desir- 
able where the magnetic variation has to be determined. The heads of 
the screws adjusting the cross-hairs should be protected by a shield to 



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404 

prevent the adjostment being lost in dragging the inatrument throng 
thickets. A separate telescope, either donble-refracting or with a 
divided object-glass, is the most suitable for the measurement of longer 
distances. The rod should be 10 or 12 feet long, divided into feet ind 
hundredths, and should be hinged in the middle, the two faces folding 
together for protection ; and the discs attached to the back. The 
ordinary Sopwith rod after a season's use was found to require reptin 
to the amount of S5.50. 

In five months of field-work a region of 180 square miles in extent 
was surveyed, including nearly 100 lakes from 7 miles long down- 
wards, besides roads, streams and hills. The wet days were employed 
in reducing stadia and micrometer measurements, and in calculating 
latitude and departure. The accuracy of the work was well tested 
by these calculations. It was found that the traverses around the sides 
of the quadrilaterals into which the country was divided, would 
close within an area of 20 to 30 feet radius on the ground, although in 
some instances the error was gpreater. Part of this error was due to tiie 
fact that the larger lakes were included in the line of the principal 
traverses, and that the measurements taken with the micrometer 
telescope were found to have a tendency to exceed the stadia measure- 
ments between the same points. This doubtless arose from a residuil 
error remaining in the corrections, which had to be applied to the 
graduation of the micrometer telescope, owing to its defective constmc- 
tion. The number of independent checks which had been secured 
during the progress of the work enabled the uncertainty thus arising to 
be almost entirely eliminated from the map. The greater part of the 
survey was included on a sheet 36 inches by 24 inches, representing an 
extent of 18 miles, by 12, a portion of which was ocean. The Atlantic 
coast was taken from the Admiralty chart, with which the surveys had 
been connected. Three plans of mining districts were also prepared on 
the same size of sheet, to the scale of 500 feet to the inch. The methods 
employed were found of sufficient accuracy to enable the surveys to be 
represented on this scale, as in these districts the closed surveys were 
more numerous and less extensive, and running errors could therefcnre 
be eliminated. 

The cost of the survey, as found by dividing the total expense by the 
area covered, is ^l&i^,^ per square mile. If the time spent in the field 
in obtaining detail for the plans, and the amount of office- work upon 
them, are allowed for, the cost per square mile of the map alone would 
not exceed $15. This does not include the expense of publication. 



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AMERICAN SOOIETY OF CIVIL ENGINEERS. 

INSTITUTED 1852. 



TRATSrSACTlOlSrS. 

NOTK. — This Society is not responsiblb, as a body, for the facts and opinions advanced in 
any of its publications. 



(Vol. XI.— December, 1882.) 

DISCUSSION 

By James P. Allen, Jun. Am. Soc. C. E., on Paper CCXLIX. 

RAPID METHODS IN TOPOGRAPHICAL SURVEYING. 



James P. Allen. — I am satisfied that Mr. Dawson's conclusion as to 
the best single instrument for a surrey of this character would be fully 
established by experiment. 

An ordinary stadia transit or theodolite, with a good self -reading rod, 
is equal to all of the duty required upon the survey which he describes. 
The preference is usually given to two stadia hairs, equally or about 
equally spaced above and below the ordinary horizontal hair of the in- 
strument. These hairs should cover about one foot on the rod for each 
100 feet of distance. They may be fixed upon the same diaphragm as 
the ordinary cross-hairs, or they may be made adjustable. Either plan 
has advantages as well as disadvantages. 

Long distances can be read on a rod of the ordinary length by taking 
first the space on the rod covered by the middle and upper hair, and 



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4U6 

afterwards that between the middle and lower hair. The stun of these 
will be the total space or stadia reading. 

With a rod of 14 feet we are thus able to read 2 800 feet, than which 
longer sights will rarely occur in practice. There is a somewhat lower 
practical limit to the distance, which can be read with a self -reading rod, 
due to the difficulty of distinguishing the figures, except under favora- 
ble conditions. 

With a clear atmosphere and the sun shining upon the rod, it is 
quite possible to read 2 500 feet. 2 000 feet might be assigned as a prac- 
tical limit with the ordinary American transit It is frequently possible 
to double this distance between stations, or turning points, by measur- 
ing from both stations to a point about midway between them on the 
line ; or this point may be taken slightly to one side, and its direction 
from the stations observed as well as the distance. The direction from 
station to station is also observed at the first setting. 

The self -reading rod is generally preferable, on account of the greater 
rapidity in its use, and also because with it a skilled assistant is not neces- 
sary. It is probably quite as accurate for a survey of any extent, the 
errors balancing each other. 

A skillful observer can read the distance upon a self-reading rod held 
on a boat, provided the motion of the boat be not too great 

The rod is adjusted to the instrument, in the case of fixed hairs, by 
measuring a base, determining the length of rod covered by the stadia 
hairs upon this base, and dividing this into spaces representing 100 feet 
each. A stencil is then made of the desired pattern and the rod marked 
for its whole length. With adjustable hairs the rod is prepared first ; a 
base is then measured, and the hairs adjusted to read the corresponding 
distance on the rod. 

The plan followed by Mr. Dawson of measuring his base from tiie 
anterior focus instead of the centre of the instrument seems to be a good 
one. The error, which appears in all stadia distances, thus becomes 
constant, and a constant additive correction must be made to each read- 
ing. The rod cannot be so graduated as to correct this error entirely. 
In fact, the plan which Mr. Dawson used does not correct it except for 
horizontal readings. However, for readings out of level a very simple 
formula of reduction may be used without appreciable error. 

With a self-reading rod the use^of tables is obviously unnecessary, ex- 
cept for reduction to the horizontal and for heights. The horizontal dis-* 



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407 

tances and the vertical heights can be obtained by tables or by diagrams; 
or, if there are only a few points, they may be calculated directly. 

Very accurate leveling can be done, provided there be a level under 
the telescope, as is generally the case. If the stadia hairs are adjustable, 
the self-reading rod may be laid off into feet, tenths and hundredths, 
and becomes a correct level-rod at once. Otherwise a correction must 
be applied to all heights. 

This method of surveying is valuable on account of its economy. 
Good preliminary surveys may be made where the funds available would 
not warrant the expense of regular methods. 

It appears to be especially useful in hydrographical surveying. 
Here the lines of sight are generally horizontal, making corrections un- 
necessary ; cutting can be avoided by judicious management, as noted 
by Mr. Dawson, and a complete instrumental survey made at a mini- 
mum of expense. 

As a method it cannot be classed in point of accuracy with chain sur- 
veying or triangulation. But, since it is susceptible of a higher degree 
of accuracy than is usually attained in public surveys, with fewer men 
and generally in less time, it seems well suited to American engineering 
l^ractice, when there is a constant demand for rapid and economical 
methods. 



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AMEMOAN SOCIETY OF CIVIL ENGINEERS. 

INSTITUTED 186J. 



TR i^JSrS^OTIONS. 

NoTB.^'i'his Society it not responsible, as a body, for the facts and opiniooa advanced la 
any of its publications. 



(Vol. XI.— December, 1883.) 



WEIGHTS AND MEASUEES. 

By Fbep. Brooks, Jon. Am. Soc C. E. 
Read June 18th, 1881. 



WITH DISCUSSION 
By Jacob M. Clark, M. Am. Soc. C. E. 



It is a common remark that in regard to metrology, harmony of 
action between the United States and Great Britain wonld be yery de> 
sirable, on account, firstly, of the magnitude of the commercial and 
other intercourse between the two countries, and secondly, the cor- 
respondence already existing between their weights and measures. This 
opinion was expressed in several of the reports made about three years 
ago by the department and bureau officers of the United States €k>Tem- 
ment in reply to a resolution of the House of Representatives which 
drew out their opinions upon metrological reform. There would be 
more force in the suggestion if past experience encouraged us to hope 
for any united action ; there is certainly reason in it, for it recognizes 
the importance of taking foreign nations into consideration ; both of the 
assertions upon which it is based require to be scrutinized. 



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409 

(1.) I will first present the facts as to whence the imports into the 
United States come ; for the next step in her metrological legislation is 
likely to relate to the business of the custom houses. The present 
enormous development of international commerce is chiefly the growth 
of the present century, and is due to the introduction of railroads and 
steamships to facilitate transportation, to the successive removals since 
the end of the Napoleonic wars of many restrictions upon trade, to the 
increase of metallic currency by the discovery of gold in California and 
Australia, and to other causes. It is only comparatively recently, there- 
fore, that the reasons for requiring international uniformity in weights 
and measures have been nearly as plainly recognized as those for requir- 
ing uniformity throughout any one nation . The official reports from 
the Bureau of Statistics of the XJ. S. Treasury Department show that 
during the year ended 30th June, 1879, the value of merchandise imported 
into the United States was S445 777 775, of which 28 per cent, was pro- 
duced in Great Britain and other countries which iise her imperial 
weights and measures ; 59 per cent, was produced in countries that have 
adopted within the last hundred years a common international system of 
weights and measures, and the remaining 13 per cent, was produced in 
countries which use various other weights and measures ; all of which is 
exhibited in detail on the accompanying diagram (Plate XXXTV.). 

(2. ) Now let us look at the second assertion, about an existing cor- 
respondence between the weights and measures of Great Britain and 
those of the United States. In the United States we have for one 
measure of length the vara,* by which, under the laws of Texas, the 
public lands of Texas are surveyed and described. For one measure of 
surface we have the arpent,t by which real estate is advertised and sold 
in the Mississippi Valley, according to the report made by the Com- 
missioner of Patents among those mentioned above. For capacity we 
have incongruous measures for liquid and dry substances, and a great 
deal of variety in the laws of the different St-ates about them, as is stated 
with considerable detail in an addendum to the report made by the Com- 
missioner of Education among those mentioned above. For instance, a 



* I am credibly infoniied that the arroba, the fanega. and other weights and meaaores of 
Spanish origin are also in nse in Texas. August 21, 1881. 

Trautwine's Engineers' Pocket Book (15th thousand, 1881) gives the vara and the legua 
as having legal values in California, the values being a little greater there than elsewhere. 

t The map of Montreal which is now hanging upon the wall of this hall has a linear scale of 
arpents. 



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410 

gallon of milk in Vermont and Massaohnsetts is 231 cubio inches ; in 
New Hampshire 282 oubio inches. The bushel, though usually under- 
stood to be a capacity measure, is for many substances defined to mean 
a weight ; the bushel of oats and the *bushel of barley have each six or 
eight different values, and for various products in the several Statea and 
Territories the legal bushel has forty diflferent weights ; 1 000 bushels 
of barley, bought in the State of Kansas at 48 pounds to the bushel, 
would become 1 500 bushels in New Orleans, where a contract for de- 
livery would, in the absence of agreement to the contrary, be satisfied at 
the rate of 32 pounds to the bushel. In the case of rye, 1 000 bushels 
would, by the same transfer, become 1 750 bushels. In Indiana a 
bushel of coal mined in the State is fixed at 70 pounds, but a bushel of 
coal mined outside of the State and sold within the State must contain 
80 pounds ! 

As for weights proper, the United States standard pound, preserved at 
the Mint at Philadelphia, is a troy pound, and is the only material weight 
or measure that has been declared to be a standard by Act of Congress. 
Diamonds and other precious stones are sold by the carat, an anomalous 
weight, of which conflicting definitions may be found. One hundred 
pounds have been made a hundredweight, and 2000 a ton, in Massa- 
chusetts since 1826 ; and probably some other States have passed similar 
laws ; I did not suppose Pennsylvania was among them. Our fellow 
member, Mr. Coleman Sellers, of Philadelphia, stated, however, in his 
very interesting address to the Mechanical Engineers, last fall, that a 
ton of 2 000 pounds is used in machine shop practice and in selling 
machinery. 

Now, in England the above described United States units are not 
within the pale of the law. The Weights and Measures Act, 1878, which 
went into effect in the United Kingdom January 1st, 1879, is chiefly a con- 
solidation of the statutes previously existing, and had for one of its prin- 
cipal objects to extirpate the various irregular weights and measures, 
which to an extent hardly credible have been customary and local stand- 
ards in England. This Act well illustrates the importance which is justlj 
attached to having uniformity established throughout the country, and 
also the method by which it is secured. Contracts by weight or measure 
are declared void unless they are according to the weights and measures 
authorized by the Act. 



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411 

I will quote a single section : 

** 24. Every person who uses or has in his possession for use for trade 
a weight or measure which is not of the denomination of some Board of 
Trade standard, shall be liable to a fine not exceeding five pounds, or in 
the case of a second ofifense ten pounds, and the weight or measure shall 
be liable to be forfeited." 

The troy pound is not a Board of Trade standard. The imperial gal- 
lon and bushel for both liquid and dry substances hold respectively 10 
and 80 pounds of water ; they were introduced into England more than 
60 years ago, and into Canada, I believe, within the last decade ; they 
are entirely independent of the measures which go by the same names in 
the United States. The imperial hundredweight is defined as 8 stones, 
and the stone as 14 pounds ; and decimal standards of imperial weights 
are not adopted by the Board of Trade except for the smaller denomina- 
tions like ounces and grains. Decimal subdivisions are permitted to be 
used, however, in expressing weights and measures in contracts. 

As an illustration of the practice in this respect, take the 19 cwts., 5 
stones, (5 pounds, 9 ounces, 15.04 drams, given in a schedule to the Act 
as the imperial equivalent of the millier (or 1 000 kilos used by the rest 
of the world, and authorized by this Act to be used as a term in British 
contracts). The similar equivalent given in the United States law of 1866 
is 2 204 .6 pounds. With difficulty do we recognize that the two expressions 
are of the same magnitude. There is a little less contrast in the equiva- 
lents of measures of length ; the first item in the British schedule is 6 
miles, 376 yards, feet, 11.9 inches ; in the United States schedule, 
6. 2137 miles. Some of our citizens who happen to remember how many 
yards make a mile, etc., and who are good at figures, can ascertain by 
computation that these are practically the same length. 

I will close by observing that one cause among others of the annoy- 
ing diversities which we have been viewing, is the disposition of particu- 
lar professions or trades to adopt what seems to them good, regardless of 
the rest of the community. Most of us see our neighbors' faults more 
clearly than our own ; so let us look for a moment with abhorrence upon 
the carats of the jeweler, and the scruples, fluid ounces, and other mys- 
terious quantities of the apothecary, and make up our minds that weights 
and measures so discordant with what are generally used ought not to 
be allowed . Then let us humbly reflect upon what the jeweler and 
apothecary would say of Gnnter's chains and links, and the railroad en- 



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412 

gineer'8 tenths and hundredths of a foot. Shall an unonnt of irregu- 
larity greater than is tolerated by old England be submitted to indefi- 
nitely by her progressive children on this side of the Atlantic? Of 
course not. It is generally agreed that the existing metrology of the 
United States must be reformed. Our physicians and druggists have 
already taken efifective action looking to the abandonment of their 
ancient apothecaries' table. Civil engineers cannot be indififerent to the 
importance of the subject, unless they are willing that their profession 
shall lose that influential position in the community which breadth of 
view and public-spirited action entitles it to hold. 



DISCUSSION, 

Jacob M. Olabk, M. Am. Soc. 0. E.— There appears to be some 
misapprehension both as to the present status of the French system and 
its inherent merits. The argument drawn from the present aspect of 
commerce, so far as it applies, is of undoubted weight. But it should 
be observed that the same or kindred arguments may be, and always 
have been, used to perpetuate errors, until resulting evils become en- 
tailed, or else have to be displaced by the force of public opinion. 

Where the French system has been made compulsory, it seems to 
have been done without much regard to the wish or convenience of the 
people ; and where its use has been made permissive, there are formida- 
ble tendencies against it. Many who were at first attracted by its alleged 
scientific foundation and systematic decimalization have had their 
views modified by maturer thought. It is an itinerary, founded on the 
earth's circumference, not novel in principle ; with no better division of 
the circle than ancient analogous systems, a palpable error in its unitary 
meter, and inferior to them in that it presents no convenient manual 
unit. On this latter point, the experience of men, as expressed in their 
systems, is a more cogent and conclusive fact, at least to a philanthro- 
pist, than any superinduced state of commerce can possibly be. The 
manual unit for general purposes, whenever founded upon convenience, 
has always ranged between 17 and 30 inches. The foot, with duodeci- 
mal subdivision, has been largely used by builders on account of its 
convenience for fractional subdivisions ; but the manual implement has 



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I 



1 1 



I 

to 



59 

* 



^ 

^ 



^' I § 



5 



I I § I 






^ 
5 




Digitized by VjOOQIC 



Digitized by VjOOQ IC 



413 

been the 2-feet rule. And it is remarkable that the duodecimal or 
Joktanic arithmetic, founded on the natural divisions of the circle, 
fractionally convenient for minor purposes, and of unquestioned an- 
tiquity, has never presented a dimension longer than 144 inches, which 
survives in our standard length of boards, the joktan of Guinea, the 
tung of Sumatra, and others less exact. The reckoning has always been 
by thousands and millions of feet. Of its enormous influence in con- 
founding metrics, mention will be made further on. 

To understand the points raised, a brief comparison and historical 
outline is indispensable. Much of the outline has to be filled in by 
severe induction, keeping within strong probabilities, and in range with 
visible points . 

The means of comparison is the ancient Egyptian and Phenician 
schoBuus or land-chain— a length of 145 iVo English feet. The cubit was 
its 1 Jo part, and the fathom (fedan) 3 cubits ; the stadium 100 fathoms, 
and the great schoenus 100 stadia, or ten miles. The Persian parasang 
was 50 stadia, or 5 Egyptian miles. Their cubit agreed with the 
Egyptian. It is at once apparent that the Egyptian itinerary was a 
surprisingly exact decimal of the mean terrestrial great circle, as we 
now understand it, divided into 3 parts ; and the parasang, into 6. The 
agrarian schoenus and cubit, consequently, were empirical decimals 
of the division into 9. Astronomers divided the celestial circle into 12 
parts ; and there was the obvious division into 4 and 8. The general 
arithmetic was decimal. For reasons presently apparent, the division^ 
of the circle by 24, 5, 10 and 15 were probably known. Here was a sys- 
tem which, on the whole, compares favorably at least with the French. 
But there existed among builders the duodecimal fancy in arithmetic, 
reckoning from the thumb or inch. Successive bisections of the joktan 
gave the vulgar fathom, the yard and the 18-inch cubit, now largely 
represented in the East Indies. This was in direct collision with the 
ancient cubit of 17^1^ English inches. 

One feature of the experiment on the plain of Shinar, which failed 
politically, was a consolidation of metrics by merging all the factors 
into a general system. The circle was divided into 360 degrees, so as to 
embrace the ungeometric divisor, 9 ; and to make things strong, both 
the degree and hour-angle were subdivided sexagesimally . A cubit was 
invented, subtending one degree on a radius of 100 duodecimal feet, that 
is, 21 inches, or more strictly, 1"/*^^-^ feet. This metric scheme was 



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414 

adopted by the first Assyrian monarchy, and divers features of it dis- 
persed among the migrating colonists. 

Then came the Hebrew system, a striking mosaic* The arithmetic 
was decimal . The cubit was taken at ^o of the agrarian schoeQua, the 
fathom, 4 cubits instead of 3, the stadium 100 fathoms, and the mile 10 
stadia. So that the great schoenus was 60 stadia, as quoted by lexico- 
graphers, and the parasang 30, or 3 miles . The itinerary was an even 
decimal of the terrestrial division into 18 parts, and the half mile or 
Sabbath-day's journey matched with the Babylonian degree. A 3-cubit 
fathom would match an itinerary founded on the hour-angle, such as 
appears in the Turkish mile, and is traceable in the braza and toesa of 
Spain and Portugal, the toise of Lorraine and Lidge, the tesa of Turin, 
and any number of caRas, klafters, passos, and the like, in various parts 
of Europe. The radial cubit, of which all the rest were known functions, 
was not obtruded, but reserved for purposes of arbitration, under the 
strongest safeguards against violation, loss or destruction. The inch 
seems to have settled at a pure decimal of the double diameter or square 
cross. The unit of capacity was a cubic duodecimal foot, divided deci- 
mally, but with fractional divisions for commercial convenience, each of 
which was even inches. The unit of weight was half a thousandth of 
the weight of the capacity unit in water (the ratio of the cone to the 
sphere), and was monumented in silver money. It is traceable in the 
avoirdupois ounce, originally a double shekel weight. There was a 
Hebrew foot, so called, not a part of their system, but simply a portable 
tenth of the joktan, for reference. It has caused much confusion by 
being divided duodecimally among those who mistook its true import 

A few years after the overthrow of the Jewish kingdom, and the 
forced expatriation of the people, and pursuant to an understanding 
between the subjugated leaders and the Medo-Persian alliance, then 
about at its zenith, Ezekiel drew up a plan of the restoration. He set 
up the radial cubit as the common measure of temple, glebe, city and 
inheritance. His arithmetic was decimal. He vindicated geometry, and 

* Thin KyHtom is rather referred to as an exintiuK fact, than ordained in the lusti' 
tiitee. Traceft of it. in connection with othern aHPignable to the other HyHtems, in the metrics 
of China. An-Nam and the BurmeKc poninRula. before the interference of EuropeanB. 
suggest that it may have been a device of thinkers at the time of the dispersion to mitigate 
the evils likely to grow out of the Babylonian plan. A curious division of the diurnal cycle 
into 18 parts appears in the •• Book of Enoch," translated fW>m the Ethiopic. 



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415 

proclaimed the divorce of direct measure from circnlar and itinerary, 
by suggeBting a reed of six radial cubits, which -would geometrically 
span but not measure the circumference. [In the sequel, the kaneh, or 
builder's reed, seems to have settled at 4 radial cubits, or the double 
diameter.] Itinerary was npt interfered with. The old system of 
weights, capacity and money was allowed to stand, with marked empha- 
sis upon decimal relations. 

After the Macedonian conquest, various foreign measures were intro- 
duced into Egypt, and metrics became much confused.* Matters were 
made worse by the Greeks and Bomans, whose itineraries were founded 
on the military pace. As a climax, the Roman Government, having 
finally denationalized the Jews, sunk the sacred cubit in the Tiber. 

This rather meagre outline explains many things which have been 
obscure. Among other things, it reconciles in an unexpected way the 
apparent conflict of mathematicians during the old revival of letters as 
to the size of the earth. Before the Macedonian conquest, Aristotle had 
announced it as the opinion of geometers that the circumference was 
300 000 stadia. Archimedes made the same statement 200 years later. 
Twenty years further on, Eratosthenes, by altitudes of the sun at Syne 
(Assouan) and Alexandria, computed it at 250 000. Fosidonias, 140 
years later, using a star at Alexandria and Bhodes, deduced 240 000 ; 
260 years more, and Ptolemy, from careful measurements in Egypt, 
brought it out at 180 000. It is too much for belief that these eminent 
men, all educated in Egypt, or any one of them, blundered seriously, or 
used less ingenious contrivances than the odometer wheel and big 
wooden triangles of Femel, in France, in 1525. But if we assume that 
Aristotle and Archimedes reckoned by the Egyptian itinerary ; Eratos- 
thenes by a 3- cubit fathom upon the Babylonian or royal cubit ; 
Fosidonias in like manner upon the Mosaic cubit, as the Saracens did ; 
and Ftolemy by the Jewish itinerary,— the results agree. 

Metrics are now so confused that a compromise, in the nature of the 
older Hebrew system, is impossible. The downMl of ancient systems, 
founded on the circumference of the earth, has been accelerated partly 
by defective divisions of the circle, and still more by the radical fault 
of using part of the arc— a function — instead of radius, as a metric base. 
And the French is no better ; in fact, worse. And all attempts of gov- 



* A Hcboina, quoted by Mr. Alexander, is simply an imported parasang. 



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416 

ernments to mend matters by artificial adjustments have but increased 
the tronble. 

One of the most instmotive instances of this bongling— because so 
pretentions — was the English attempt to fit duodecimal arithmetic into 
itinerary and the English land measure. The latter is of Oriental origin. 
Acre is a Persian word, and perch a modified Boman name for a PersiAn 
thing. To understand the movement, it should be noticed that the 
radial cubit was always in a somewhat perplexing relation to the 2-feet 
rule of the builders. To enlarge the latter would destroy the decimal 
correlation of the inch ; and to reduce the former would mar the measure 
of inheritance. To prevent confusion, the radial cubit was disused among 
builders, without any assertion on their part that the 2-f eet rule was or 
ought to be a veritable unit. In their symbolic system, its division is 
explained to refer to time. It is not a measure, but a witness, an index 
to the circle, whose properties are to be learned by geometry ; and it 
suggests division by three and the parallels. In the face of this broad 
hint, the philosophers lugged in the yard, a quarter as long as a standard 
board. The rod was clipped to 198 inches, 6J yards; the perch of 
England and Ireland stretched to 252 inches, 7 yards. Taken as a diam- 
eter, 7 yards, by Archimedes' rule, demands a circumference of 22, a 
perfect decimal chain of 100 new-bom links ; the broad acre was made 
10 square chains, 10 times as long as broad ; but reduced to a square, 
its side is neither perches, yards, chains, links, feet or inches. But the 
circle was squared ** according to Gunter," by board measure. The 
mile was made 80 chains, and fits nowhere. It is doubtful if the inch 
escaped degradatioa. The Pyramid, with the height of its remaining 
frustum to the theoretical height as 24 to 25, can scarcely be called a 
''witness" to existing measures, unless on the score of martyrdom. It 
is beheaded, skinned and well-nigh disemboweled. 

I have elsewhere (correspondence on Standard Time) suggested an 
arrangement on the radial cubit with a correlated inch, without the 
duodecimal tangle, and with itinerary founded on the hour-angle. 

From a cursory examination of Alexander's ''Weights and Meas- 
ures," published 32 years ago, it is apparent that when the present 
French system was instituted, the number of available analogues in 
Europe and the East, susceptible of adjustment into a more perfect sys- 
tem, stood about as follows : 



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417 



Badial cubit, 175, of which were in France and dependencies 12 . 



Metric perch, 12, 
** rod, 30, 
** reed, 40, 
** acre, 35, 
*' fathom, 28, 



• 6. 

6. 
12. 
15. 

6. 



The inch being subordinate, it seems a fair question whether, for a 
general system, weights and capacity should not be founded on the 
radial cubit. Engineers, from their training, are as able to endure the 
present evils as are other men. But this very fact makes them keenly 
alive to existing defects ; and at the same time, as a matter of foresight, 
inclined to deprecate changes hastily made ; and particularly, in the 
light of past human experience, to avoid invoking governmental interfer- 
ence, until it shall clearly appear to the public, as well as to themselves, 
that such changes are in the direction of ultimate maximum propriety 
and utility. 



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AMERICAN SOCIETY OF CIVIL ENGINEERS. 

INSTITUTED 1852. 



TR^NSA-CTIONS. 

NoTC— ThiH Society is not responsible, as a body, for the facts and opinions adranoed 
in any of its publications. 



CCIA. 

(Vol. XI.— December, 1882.) 

ON THE CARE AND MAINTENANCE OF IRON 

BRIDGES. 



By Henbt D. Blunden, M. Am. See. 0. E. 
Bead October 18th, 1882. 

WITH DISCUSSION 
By Theodore Cooper, M. Am. Soc. C. E. 



Many valuable papers have been both read and discussed before this 
Sooiety on the design and construction of iron bridges, but of their 
care and maintenance after erection we have heard very little. Indeed, 
it seems to be the prevailing opinion among almost all classes, that 
when an iron bridge is once erected, painted and the floor down, it is 
to last forever, requiring no care except an occasional coat of paint, and 
as an omission of this latter does not immediately affect the strength of 
the structure, it is frequently neglected. 



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419 

After a close examination of a large number of bridges in different 
parts of the State dnring a period of nine years, I am satisfied that they 
are invariably shamefully neglected. 

As a general rule, the immediate care of iron bridges is left to men 
who know nothing either theoretically or practically of the design or 
manufacture of the structures they look after. To screw everything up 
tight seems to be the order of the day, regardless of consequences. If 
a rivet becomes loose they replace it — perhaps the same rivet two or 
three times in as many months — seldom asking why such rivet becomes 
repeatedly loose. 

Some of the causes of undue wear and tear to bridges are as follows^ 

The ties not having an even bearing on the stringers, with rails not 
properly spiked to the ties. The result of a passing load, with this con- 
dition of affairs, is a constant pounding, first from the rail to the tie, 
and then from the tie to the structure. Imperfect track at the bridge 
approaches, and too large openings at rail joints immediately on the 
bridge, are often the causes of very severe shocks. 

The expansion gear (rollers, &c.) is generally out of sight and hardly 
ever kept clean. Insufficient freedom is often the cause of serious 
trouble. The writer, in 1875, saw the fixed end of a 180-feet span, 
double track railroad bridge push the granite pedestal to which it was . 
bolted into the back wall, on account of the free end being blocked by 
the fixed end of the following span. 

Improper anchoring down of the fixed end is another source of 
trouble, especially if the bridge be on a grade. For instance, in a 
double track, two truss, through bridge, the tendency is for one of the 
trusses to move in the direction of the traffic, the other remaining 
nearly stationary ; in such a case the lateral system has a good deal more 
to do than it was designed for. 

Poor masonry is also the cause of much mischief. No amount of 
anchoring or care with the rollers is of any use, unless the masonry be 
in a condition to resist the thrust of expansion and contraction of the 
structure. 

The free action of friction rollers is often blocked by the accumula- 
tion of dirt in front of and around them ; cinders ground to powder by 
the action of the rollers will, after being moistened by rain, form a con- 
crete so hard that a hammer and chisel are required to remove it. If 
this is not frequently done the movement of the rollers will eventually 



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420 

be prevented, and the truss most then buckle, slide on top of the rollers, 
or move the bed plates. 

Cast-iron pedestals are often so constructed that drain-holes are 
necessary. When these holes are over the rollers they invariably be- 
come channels for all kinds of dirt as well as water. 

Imperfect, or rather uneven, adjustment of the laterals will give a 
wavy motion to the trusses under passing loads, causing a working at 
the joints. This is especially dangerous with cast-iron chords or wronght- 
iron chords with cast joint boxes. 

In bridges with floors suspended from \J bolts, severe shocks are 
often given to the structure by the uneven bearing of the cross-beam 
on its seat. If the hangers be in pairs, unless most carefully tightened 
up and the seat given a uniform bearing, one pair will carry by far the 
largest part of the load. The same trouble occurs with the stringer 
seats on the cross-beam. 

The over tightening up of the counters will relieve the main rods and 
chords of a part of their dead load. Under this condition of things, on 
a load being applied, the counters are improperly strained, and the main 
rods and chords receive more or less shock, ending in the final breaidng 
of the counter. If the chords be not properly packed, a chance is given 
for the eye-bars to move ; the result of this is either the cutting of the 
pin or the distortion of the pin-hole. 

The writer tested a sample cut from a counter broken under the 
above-mentioned conditions, with the following results : 

Ultimate, 44 000 pounds per square inch. 

Fracture, large crystaLj. 

Elastic limit, 36 000 pounds per square inch. 

No elongation. 

No reduction. 

Although corrosion may hot materially affect the strength of a bridge 
for many years, it most assuredly will in the long run. The writer, in 
the case of one railroad crossing over another, removed from a three by 
(3" xl") one inch flat bar of iron, in the bridge, scales almost one dV') 
sixteenth of an inch thick ; this bridge had only been erected (10) ten 
years, and had been painted twice. 

Without going into the question of design, there is one point that 
appears to the writer as faulty. For instance, in a double track, two 
truss, through bridge with four parallel stringers, it is customary for 



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421 

the trass pedestals to rest on friction rollers at one end, and to be bolted 
to the masonry at the other, while the ends of the stringers rest npon 
sliding plates or a timber wall plate bedded on masonry. 

To obtain uniform results, should not the ends of the stringers rest 
upon a beam connected to the end pedestal, thereby throwing the en- 
tire weight of the structure on the two fixed and two movable points ? 

False economy is often the cause of a very poor floor. For the sake 
of saving a few pounds of iron, the flange section of a stringer is made 
of two angles and a short cover plate, thereby necessitating a variety of 
notching down to give the ties an even surface. A section of two larger 
angles would obviate any notching except the ordinary sizing of the 
tie. 

Corporations very seldom take into consideration the cost of a floor 
and its future maintenance in canvassing proposals for bridges. Many 
of those now built have floors which it is almost impossible to renew, 
either in whole or in part, without disturbing the entire structure. 

Suggestions for the Case and Maintenance of Iron Batlboad 

Bridges. 

Track. -^The track for a distance of 500 feet on each side of the 
bridge must be kept in perfect line and surface. If on a curve, the 
proper super-elevation should be maintained and the rails carefully bent, 
not sprung, to the required radius. 

When a bridge is at the foot of a grade, an elastic timber floor, upon 
which the rails are to be placed, must be carried back from the abut- 
ments at least 50 feet. This is especially necessary when the filling 
behind the abutments is of material easily affected by the frost. 

. THes, — Ties must be of sawed timber, evenly spaced and carefully 
sized to a uniform depth at the stringers, upon which they should have 
a full and even bearing. Whenever a tie becomes soft and is cut into 
by the stringer, or by the rail, a hard wood shim must be used until the 
tie can Jbe replaced. The rails must be well spiked and drawn down to 
every tie ; and at the lowest temperature the opening at the rail joints 
must not exceed i of an inch. 

Qtiard Timber a. — Guard timbelB, notched and screw-bolted to the 
ties, must be placed upon every bridge ; they must be drawn down 
tight to the ties and kept so. Whenever the guard timbers extend be- 



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422 

yond the bridge, they most not be rigidly connected with the guard 
timbers upon the bridge. All old spike and bolt holes in ties or goard 
timbers mnst be plugged. 

WaU Plates.— 'Where timber wall plates are used, care must be taken 
to g^ve them a full bearing upon the masonry. 

Masonry. — The piers and abutments must be kept clean and free 
from cinders and refuse material. All joints should be well pointed up, 
and frequent examinations made to detect fractures, or any signs of 
unequal settlement or movement of any kind. Whenever the masonry 
appears in the least degree insecure, a detailed statement of the facts 
should be sent at once to the Chief Engineer. 

Iron Work or Bridge proper. — Frequent and careful inspection must 
be made of all the iron work of the bridge, and especial care given to 
the friction rollers, pedestals and cast-iron work as being the parts most 
liable to g^ve troable. The rollers must be kept clean, so that they can 
move readily, and also be placed and kept at right angles to the line of 
bridge. If they cannot be cleaned from the outside, the trusses must 
be raised, the roller frames taken out, cleaned and replaced. Pedestals 
must be examined frequently to see if they are cracked or otherwise 
insecure. The nuts on the anchor bolts must be set up tight, and the 
drain- holes, if any, kept free and clear. 

Cast-iron in any form is objectionable in a bridge, and particularly 
so when in the shape of chord joint boxes. These require constant 
watching, particularly in cold weather ; and should any cracks or im- 
perfections be discovered, a report of the defect, as much in detail as 
possible, should be at once submitted to the Chief Engineer. 

The rivets in the bridges should be examined from time to time, and 
loose ones cut out and replsiced as soon as possible. If the web sheet be 
torn and the hole becomes elliptical, it should be reamed out and a larger 
rivet inserted, that is, provided the elongation be not more than ^ 
of an inch greater than the diameter of the old rivet. Should the 
plate be torn to a greater extent, or the rivets after replacing become 
repeatedly loose, a full and accurate description of the defective parts 
should be submitted promptly to the Chief Engineer. 

When a bridge has been put in proper adjustment, the nuts and 
turn-buckles on the hangers, counters, lateral and sway-rods must be 
clamped in place and not altered. In bridges of ordinary span all of the 
parts will expand and contract so nearly alike, that loosening or tighten- 



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423 

ing the rods is unnecessary, and only productive of excessive strains in 
some of the members of the truss. 

Examinations, ^Thorough examinations of every bridge should be 
made as often as possible, certainly not less than once in every thirty 
days, and more frequently upon those bridges which have some special 
weak points. Everything pertaining to the bridge and its surroundings 
should be carefully inspected, and a report, giving the condition of the 
masonry, superstracture and track, with any recommendations thought 
necessary, should be forwarded to the Chief Engineer, and in no case 
must extensive repairs or any alterations be made in a bridge until the 
same shall have been approved by him. 

Painting. — All of the iron work should be painted at least once in 
every three years, but should rust spots appear between the periods of 
painting, they must be scraped and re-painted as soon as detected. 

Whenever the entire structure is to be painted, all rust must be 
thoroughly scraped off or otherwise removed, and the new paint applied 
evenly and not daubed on. 

The above suggestions are presented by the writer as the result of an 
extended experience on a long line of road (the New York, Lake Erie 
and Western), with the hope that engineers of other railroads will also 
submit their ideas, and that out of the resulting discussion a greater 
knowledge of this important subject may be generally diisseminated 
among those having the care of such structures. Greater safety to the 
public will certainly be the result. 



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424 

DISCUSSION 

ON THE CARE AND MAINTENANCE OF BRIDGES. 
By Theodore Cooper, M. Am. Soo. C. E. 



The rusting or corrosion of wroaght-iron at ordinary temperatares is 
a yery important matter of consideration. 

The example given by Mr. Maodonald^ of the corrosion of an iron 
rod set in sulphur is not an uncommon one ; numerous instances, how- 
ever, can be given where iron set in sulphur has not corroded. The 
explanation, to the writer's mind, is a simple one. There is no chemical 
action between pure sulphur and iron at ordinary temperatures ; these 
two elements only uniting at high temperatures— above red heat. But 
ordinary commercial sulphur generally contains sulphuric and sulphur- 
ous acids, produced by the oxidatibn of the sulphur during its process 
of sublimation. These acids are the immediate corroding agents when 
the impure sulphur and iron are in contact. 

Suc}i sulphur should be thoroughly washed before being used. 

In general, the rusting or corrosion of iron only takes place in the 
presence of an acid and moisture. 

In dry air at common temperatures, or under pure water free from air 
and carbonic acid, iron does not oxidize. Neither does it oxidize in dry 
carbonic acid gas ; nor to any great extent, if at all, in damp oxygen. But 
in the presence of moisture and many acids the corrosion takes place 
readily and continuously. 

The most common agent towards corrosion is carbonic acid gas. 

Prof. Calvert found that damp air with a slight addition of carbonic 
acid produced a rapid oxidation ; the process being, first a production of 
protoxide of iron, changing to the carbonate and then passing to the 
hydrated oxide or ordinary rust. Though th«i carbonic acid was the 
active agent in bringing about the combination, the carbonate of iron 
remained in small quantity— an apparent process of transfer or disposing 
influence. 

As our atmosphere contains carbonic acid gas and aqueous vapor, 
and as all natural waters contain air and generally carbonic acid in solu- 
tion, the rusting of iron is universal. It varies, however, in the degree 
of rapidity according to the conditions of the special location ; the 



* In a rerbal discuBsion of the paper on the care and maintenance of bridges. 



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425 

dryness of the air in cert&in regions making the action an exceedingly 
slow one, while in others the excess of moisture and gaseous acids pro- 
duce an exceedingly rapid corroding action. In tubular bridges, tunnels 
covered with iron girders, and the overhead parts of bridges, the iron 
work is especially subject to corrosion, due to the excessive amount of 
moisture (condensed steam), carbonic aoid and frequently sulphurous 
acid discharged upon the exposed surfaces from the locomotives. 

While the sulphurous acid, if present, is a very active agent in pro- 
moting corrosion, the greatest factor is undoubtedly the carbonic acid gas. 
An analysis of a sample of rust taken from the Conway Bridge gave — 

Sesquioxide of iron 93 . 094 per cent 

Protoxide '* 5.810 

Carbonate " 0.900 

Silica 0.196 

Mr. Wm. Kent found in rust taken from a Pennsylvania Railroad 
bridge, where it was exposed to the action of the escaping gases, car- 
bonic acid in considerable quantities, but only traces of sulphuric and 
sulphurous acids. 

Under fresh or under salt water the corrosion of iron is largely in- 
fluenced by the presence and amount of air and carbonic acid gas. 

The action generally appears to be greater where the iron is alter- 
nately wet and dry. 

The caustic alkalies and alkaline earths prevent the oxidation of iron 
by neutralizing the acids. Iron, therefore, does not corrode in alkaline 
solutions or when imbedded in lime. 

The testimony in regard to the action of a thin coating of lime white- 
wash upon iron is contradictory. The writer has seen many cases where 
whitewash has corroded iron rapidly ; others testify to its thorough 
preservative qualities. The difference may consist in the addition of 
other ingredients to the solution ; for example, it is often customary for 
white washers to add common salt to the lime solution to increase the 
hardness of the coating ; again, others add glue or similar material to the 
lime to increase its adhesive qualities. The one containing the salt 
would undoubtedly corrode the iron, and the other with the glue would 
not do so. Whether a thin layer of lime only, after the lime had taken 
up its full equivalent of carbonic acid, would continue to act as a pre- 
servative, is doubtful ; for from its hydroscopic character it would readily 
convey moisture charged with the destructive acid in to the surfaces of 
the metaL 



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426 

As to hydraulic cement, the evidence is not so positiye. Mr. Thos. 
C. Clarke, M. Am. Soc. C. E., sajrs, in his report upon the Niagara 
Bridge, that on uncovering the anchorage links he found the iron as 
perfect as when put there, without the slightest sign of rust, though 
the mortar was saturated with moisture and the whole foundation evi- 
dently sarrounded by water-bearing strata of rock. Genl. M. G. Meigs 
says he found a wrought-iron pipe laid in cement concrete, honey- 
combed and leaky after twelve years* time, and he learns from plumbers 
that in their experience American cements corrode iron. 

This different testimony in regard to the action of cements may pos- 
sibly be explained by the different circumstances of each case— such as 
the relative compactness and depth of the cement in which the iron is 
imbedded. 

There is a possibility, however, that in certain cements the silicates 
may be soluble in water, and thus furnish the acid agent toward corrosion. 
Mineral wool made from furnace slag very closely approximating the 
composition of hydraulic cements has been found in certain cases to 
corrode iron very rapidly. It was claimed that this was entirely due to 
the hygroscopic character of this material, but recent instances reported 
to me would appear to lead to the belief that the wool in the presence 
of water not only corrodes the iron, but also disintegrates and hardens 
into a solid mass. 

Wet coal ashes corrode iron very rapidly. 

Mr. Wm. Metcalfe, M. Am. Soc. O. E., states that a wrought-iron 
pipe buried in coal ashes was completely eaten away in one year's time. 

As a curious instance of the slight causes which promote oxidation, 
the experience of a manufacturer of fine cutlery was related to me. He 
found at one time a large portion of his goods being returned to him as 
in damaged condition ; instead of the bright clean surfaces for which 
such articles are noted, he found rusty, deeply oxidized blades. After 
much anxiety and watching to determine the cause, whether it was damp 
paper, the ill-will of some of his agents, or other cause, it was located 
upon the man who sorted and wrapped the knives into packages. Every- 
thing he touched was found to rust, from the peculiar acid character of 
his skin exhalations. 

Similarly, it is well known that some persons cannot carry pocket- 
knives or bright iron articles, as keys, etc., about their person without 
their becoming very rusty. 



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427 

The rusting of iron proceeds with great rapidity after it has once 
oommenoed, because the rost of iron is a ready absorber of moisture and 
gases, and it thus constantly conveys new elements of destruction in to 
the yet unchanged metal. 

It is to this fact that the great difference in the rusting of used and 
unused rails, machinery and tools, is due. The jars and vibrations to 
which the one is subjected keep the surfaces clear of accumulated rust, 
that would act as storage reservoirs for the corroding elements. 

There is often much misconception in regard to the amount of iron 
contained in a certain thickness of rust. Dense compact rust may con- 
tain enough iron to equal | or i of its thickness, but the looser and 
more common kind of rust will not contain over i of its thickness in 
pure iron. In other words, rust i inch in thickness will contain from 
1^0 to 3^2 inch of iron, according to the density of the rust. 

The preservation of iron from corrosion is a subject of vast import- 
ance, and has given rise to many expedients more or less effective, 
such as alloying iron with other metals, as chromium, tin, copper, 
arsenic, &c., to obtain a less corrodible metal ; plating the surfaces with 
other less oxidizable metals, as nickel, tin, copper, silver or gold ; coat- 
ing with zinc, a metal that is readily oxidized upon the surface, but 
whose oxide, when formed, becomes a protection to any further oxida- 
tion (when not subject to other acids than carbonic acid gas) ; coating 
with fused mineral enamels ; covering with laquers ; coating with mag- 
netic oxide of iron by the processes of Barff or Bower, by subjecting to 
high temperatures and the presence of moisture ; and lastly, the use of 
paints of innumerable characters. 

For general engineering structures, the coating given to iron sur- 
faces for their protection against corrosion must be not only moderate 
in cost, but of such a character as to be readily renewed when removed 
by accident or design. It must also differ from zinc in being able to 
resist the corroding action of sulphurous acid gas and the chlorides, in 
locations where these may occur. 

This practically reduces us to the use of paints (using this term to 
include not only the paints proper, but varnishes, oils and other materials 
applied in a liquid form). The relative merits of the paints depend upon 
their durability, adhesiveness and imperviousness. The cracking of the 
paint and want of adhesion produced by too rapid drying of the paint, 
and the want of adhesion due to the presence of rust upon the surfaces 



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428 

of the iron, are the most frequent caases of failure in the better classes 
of paints. All rust should be carefully removed from the surfaces of 
the iron before painting ; a coat of raw linseed oil then makes an ex- 
cellent covering for the surface, elastic, perfectly adherent, and a good 
durable substratum for future coverings. In order to get our iron work 
out of the shops quickly and in a condition to be handled, we resort 
too often to quick-drying paints, to the future injury of the work. 

As to the pigment to be used for the covering of this substratum, 
red lead, oxide of iron, &c., each have their own advocates. 

The maintenance of iron bridges is so dependent upon the detail of 
their design, and the method and character of the inspection, that it is 
very important, both from .points of economy and of safety, that the 
supervision of these points should be given to competent men. 

The original design aflfects the maintenance and care of our bridges, 
not only by the form and proportions of the structure and its details as 
to strength, but also as it affects the accessibility for cleaning and paint- 
ing, the freedom from lodgment of water and dirt, the amount of surface 
exposed to corrosion, the number of parts subject to adjustment, and 
the facility of repair and renewal of the ties or wooden floor. 

The writer has seen bridges recently constructed, and which have 
been accepted by engineers of an important railroad, that have their 
wooden floors built into the iron work in such a manner that a broken 
or decayed tie cannot be replaced except by removing the whole bridge 
floor. 

The inspection of bridges should be something more than the super- 
ficial examination of the track- walker. To know that every member is 
doing its duty properly, and to discover the reason when such is not the 
case and the remedy to be applied, requires the supervision of a more 
intelligent class of men than usually are delegated to this work. 

Of hundreds of bridges examined during past years by the writer, it 
would be safe to say that not more than ten per cent, of them were 
found in a condition to do their best duty ; many were badly neglected, 
and some positively dangerous ; all showing a positive want of intelli- 
gent inspection and supervision. It would undoubtedly be true economy, 
and certainly a just duty to the public, for every railroad to have its 
bridges carefully and intelligently examined at least once a year by a 
special expert. If it accomplished no other end than to check and 
educate the ordinary local inspectors in a proper execution of their 
duties, it would pay for the expense. 



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AMERICAN SOCIETY OF CIVIL ENGINEERS. 

INSTITUTED 185 2. 



NoTB.'Thl« Sodety is not retpoDsible. as a body, for the facts and opinions advanced in acy 

of its publications. 

CCL,II. 

(Vol. XI —December, 1882 ) 

A PECULIAR PHASE OF METALLIC BEHAVIOR 



By O. E. MiCHAELis, Captain of Ordnance, U. S. Army, M. Am. Soc. C. E. 
Bead at the Annual Convention, May 17th, 1882. 



WITH DISCUSSION 
By T. Egleston, M. Am. Soc. C. E. 

Last September, in the ordin^y coarse of business, an invoice of so- 
called gilding metal, presumably an alloy of copper and zinc, was 
received at the Frankford Arsenal, the Government cartridge manu- 
factory. I am somewhat cautious in the use of descriptive terms; for 
up to the present, for various reasons, I have not succeeded in witness- 
ing the mixing, melting, casting and rolling of the metal. 

The contractor, owing to the uniform success of his output, has been 
deservedly considered the maker of our standard sheet cartridge copper. 

This particular delivery was subjected to the usual treatment, met 
every demand, underwent every proof, in the customary satisfactory 
manner, but failed in the firing test. The contractor was notified, at 
once appeared, and saw convincing evidence of the failure. He stated 
positively that this especial lot of metal had been treated in precisely 
the same manner as the accepted invoice immediately preceding it, and 
that he was unable to account for its shortcoming. After a moment's 
reflection, with a smile of apparent satisfaction, he turned to me, 
saying : ** By George, it must be something in the air here." 



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430 

Tkots. 

The tests to which cartridge metal is subjected may be divided 
into— 

1st. The shop, or working test. 

2d. The laboratory test. 

3d. The powder-proof. 

The shop test includes a careful inspection, by trained men, for dis- 
coverable defects, the fabrication of, say a thousand, shells in the 
ordinary way, under the immediate observation of expert attendants, 
and the running through of a limited number without annealing. This 
last may be called the crucial working test. Card No. 1 (Plate XXXV.) 
shows its progi-essive stages. The severest trial to the metal is, prob- 
ably, the reduction in the tapering machine ; if it be an inferior or 
unsuitable material, the case will buckle or split. 

Only thorough honesty and consequent adaptability will enable the 
metal to sustain the searching practical strain upon its integrity, due 
to the '*cold shut'* drawing, heading and tapering incident to this 
proof. 

The laboratory test includes the determination of the mechanical 
qualities of the metal, principally by. means of a *' Thurston Auto- 
graphic Recording Testing Machine," specially built for the purpose 
at the Stevens Institute. 

The usual autographic strain-diagrams, exemplified in the accom- 
panying plates XXXVI., XXXVII., XXXVIII., are obtainei, calculated, 
and the results compared with standards established by experience. 

In addition, the metal is subjected to a '^ bending*' proof, intended 
to serve as a specific test of its ability to stand ''folding." Strips, 
i inch wide, are doubled (see Card V., Plate XLL) under a pressure of 
1 200 pounds, and the angle of opening until the metal " gives " is 
measured, and recorded as the bending angle. 

Comparisons of specific gravity are also made in the laboratory, and 
finished cases are tried in the eprouvette, the final stage of what may be 
called, for want of a more expressive name, the static inspection of the 
metal. In the eprouvette, a full description of which may be found in 
the report of the Chief of Ordnance for 1878, the case is held in a 
chamber, the counterpart of that of the service arm ; a constant weight 



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431 

rests upon its charge by means of an appropriate stem. The smallest 
weight of rifle powder required to produce the desired efifect is taken as 
an index of the practical value of the worked metal. Cards IT. and III. 
(Plates XXXIX. and XL.) illustrate the results of this procedure. 

Card III. (Plate XL.) shows the usual shearing of the head. 

A ring is simply pressed out beyond the rig^d edge of the chamber— 
a characteristic of all suitable metal. 

Card n. (Plate XXXIX.) shows the rather unusual phenomenon of 
** bursting/' a separation between the *' fatigued " central portion of the 
head, under the immediate influence of the punch, and the less tried, 
because less supported, annular fold. 

The occurrence of this phenomenon, under normal conditions (the 
meaning of this limitation will be explained hereafter), shows that the 
metal is not suitable for this especial purpose. 

We now come to what, in contradistinction, and for a reason already 
assigned, I will call the dynamic inspection— the powder proof. 

The cases fabricated during the shop test are loaded with service 
charges and bullets, a certain percentage with an established increased 
charge, and are flred from the service arms ; the pressure required to 
extract the fired cases, a function of the elasticity of the material, being 
measured, recorded and compared with the standard limits. 

This completes the inspection of the metal ; the satisfactory accord- 
ance of all the tests determines its acceptance. 

I have now briefly sketched the severe ordeal through which our 
cartridge metal must pass before reception, and the behavior of the lot 
— the occasion of this paper— differed in no respect from its predecessors 
or successors under these trials, the extraction even being usual ; and 
yet the cases burst in the gun — of course, a fatal defect. 

Card I.,* Plate XXXV., shows the working test of this metal — a case 
drawn, headed and tapered without annealing. 

Plates XXXVI., XXXVII. and XXXVin. are autographic strain- 
diagrams of this especial metal and the accepted lot which replaced it 

No. 1, Plate XXXVI., was taken at the time of its delivery, and Nos. 
2 and 3, Plates XXXVIL and XXXVIII., recently, from reserved, 
sheets. The strips are delivered annealed, but, to make sure of its uni- 
formity, I had some re-annealed, and Plate XXXVIH. shows the result. 



*When thia pApor waa read the actual specimens referred to were exhibited on cards. 
From these Hpecimeus the plates have been prepared. 



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432 

It is unnecessary here to give the data of the diagrams— all were 
within limits, as maj be seen. 

Card m., Plate XL., shows the eprouvette proof of both the rejected 
and accepted metal ; no difference of behavior is perceptible. 

Card rV., Plate XLI., shows the failure in the gun. During the 
proof of this metal last September portions of the head were actuallj 
burst off, but, unfortunately, I did not preserve these specimens, and in 
my late experiments I succeeded in obtaining only the class of casualties 
illustrated on the card. My theory as to the cause of this T will mention 
later. 

Card 11. , Plate XXXIX., if its results had been obtained in the 
eprouvette under normal conditions, would show a metal of which bursts 
in the gun might be predicated almost with certainty, yet the rejected 
metal gave no indication of this kind. 

The cases on Card II., Plate XXXIX., are made from accepted metal, 
but under abnormal conditions. A die without a counterbore was used 
in their fabrication, thus enabling me to have the heads " set up " about 
tiAjT, of an inch beyond our limit ; the consequent increased fatigue de- 
moralized the metal, and it gave way as shown. 

From my recent experience with this rejected metal, I may, in pass- 
ing, say that I believe it in a measure confirms the theory of refresh- 
ment first expounded by a member of the Society ; it appears to be in 
better condition now than at th^ time of its rejection seven months ago. 

No adequate reason can be assigned for the final failure of this metal, 
that so successfully passed through all the exhaustive tests established 
by extended experience and profound theory. It simply ** broke down " 
in an inexplicable, unexpected manner. 

Though but a straw, this failure leads my mind to harbor the hereti- 
cal misgiving that preliminary static tests of materials furnish data use- 
ful only in the solution of questions in the calculus of probabilities. 
Nothing positive can be drawn from their consideration. 



DISCUSSION. 

T. EoLBSTON, M. Am. Soc. C. E. — Mr. President : The question of 
the manufacture of cartridge metal and its uses is one which has inter- 
ested me greatly for several years past, and on which I have made a large 
number of investigations. This cartridge metal is not a material of con- 



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stant composition. It is sometimes made of brass, containing a very 
large quantity of zinc, and sometimes of copper, containing only a very 
small percentage of zinc, sometimes only just sufficient to make the 
copper draw with certainty. This latter material generally passes under 
the name of gilding metal, while the other, which is brass, is known 
under the name of cartridge metal, if it possesses the qualities required 
for the manufacture of cartridges. 

In the course of my examination of this material I have frequently found 
that pieces of apparently the same metal, and under apparently the same 
conditions, taken from the same batch, but generally made from difiEerent 
sheets, would act very differently, some not being at all suitable for the 
purpose, and others being entirely up to standard. After examining 
cartridge metal, my attention was called by the manufacturers to the 
apparently unaccountaJt)le failures of punched and spun brass. These 
failures are so much taken as a matter of course that a certain percent- 
age is regularly expected and allowed for in the contract specifications 
which are made for this material. 

I shall, probably, at some future time have something further to say 
to the Society on this subject, but at present I merely wish to call their 
attention to the fact, that I do not consider the failure in any of these 
metals either necessary or without a cause. 

We are too much in the habit of considering alloys as chemical com- 
pounds, and as being constant in their composition, in the same way that 
metals are. We consider that the metals are homogeneous, because w& 
are in the habit of supposing that they do not give way except under 
well-defined circumstances, and we are not in the habit of examining 
very closely their physical condition after they fail. Alloys are not of 
constant composition, nor are they generally chemical combinations. It 
may be true that the materials composing the alloy are also in different 
conditions in different parts of the same piece. Probably some of you are 
aware what a delicate metal copper is, and what a very small percentage 
either of its own oxide or of other impurities will ruin it for commercial 
purposes. In the hundreds of samples of the ordinary brands of com- 
mercial copper which I have examined, I have not found, until within 
two years, since the perfection of certain of the processes of refining^ 
copper that could even be called commercially pure. It generally 
contains, besides oxygen, small amounts of lead, zinc, cobalt and nickel. 
This is true to a great extent of the coppers produced in the great Ap- 



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434 

palachian range, and to a less extent of those of Lake Superior, which 
haye always been considered, nntil copper began to be produced from 
Arizona, as the best copper that the world has ever seen. This pore 
copper may be spoiled in the refining or in the melting by which brass 
is to be made. 

The zinc contains many impurities. There are but two or three 
places, and those in this country, where a chemically pure zinc can be had. 

We will, however, suppose that these two metals are pure when they 
are delivered at the works, and that it is desired to make brass of a fine 
quality. A workman, by carelessness in the management of the fire, 
may cause so much oxygen to be absorbed by the melted copper that the 
materia) is unfit for use before the zinc is added to it at all. After the 
copper has been melted the zinc is added. If this zinc is impure there 
is a still further deterioration of the metal. If the materials are left too 
long in the fire, or are not left there long enough, there will be a still 
further deterioration of the metal. If the brass is well made and is 
poured properly into the moulds, there will be a union of the copper 
with the zinc which will be partly chemical and partly mechanical. If 
this union is perfect, or nearly so, the brass resulting will be good. 

We will suppose that up to this point everything has gone properly, 
and the brass, in slabs, is now ready to be delivered to the manufacturer. 
In order to get it into shape, it must be treated mechanically. To do 
this it must be made to pass between rolls, and brought to a certain 
width and thickness. In rolling it down it becomes brittle ; it must then 
be annealed. If it is annealed at the proper temperature, no injury is 
done to the metal. If the temperature is too low, the brass will be too 
hard when it goes under the rolls again, and may become deteriorated 
or even brittle from an unequal flow of the two metals of which it is 
composed. If the temperature is too high, it may be that the more 
volatile metal will begin to separate, so that, supposing the brass was 
good at the time it was delivered to the manufacturer, it may be injured 
first in the rolls, and second in the annealing. What may take place in 
the rolls is, first, producing the crystalline form which renders it brittle, 
and, second, if the pressure becomes very high, the absolute separation 
by cold flow of the two metals, which, as the rate of flow is different, 
will separate diflerently, and, consequently, the metal will be worthless. 
I have seen many tons of this material in the manufactories of the Nauga- 
tuck Valley, which is perfectly useless except to be ro-melted. 



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435 

If now the temperature in the annealing furnace is too high, the zinc 
will ** start,*' as the manufacturers say, that is, it will commence to sep- 
arate from the copper, and exactly the same phenomena, but produced 
in a different way, will take place ; that is to say, a flow of the metal has 
taken place, but it has been produced by heat, the result, in both cases, 
being in exactly the same condition, and the sheet metal made is worth- 
less, except for purposes of manufacture. 

In the manufacture of cartridges, this operation of annealing and of 
compressing the sheet metal takes place many times, and there are many 
opportunities for producing these results. I have not generally found that 
the material is wrongly treated in the hands of the cartridge metal manu- 
facturers, for their work is usually done automatically. In almost every 
case where I have had the opportunity of tracing it, the defect has been 
found in the sheet metal delivered to the manufacturer. It had been 
either over-heated or over-compressed. The zinc had ** started,'* and 
the material failed for this reason. 

I have sampled as many as 500 000 cartridges in a factory by firing, 
and found that many could only be fired once, a few would fail on the 
second firing, still fewer would fail at the third, and that we could occa- 
sionally find in the same batch of metal, cartridges which would fire 150 
times. In every case the failure was due to the same cause, and after 
an examination of hundreds of them, I became satisfied that this cause 
was either too great compression or too much heat ; this being true even 
in those samples which contained a minimum quantity of the volatile 
metal. It is even possible to produce a cold fiow of the metal to such an 
extent that, with a sufficient pressure, the two metals may be entirely 
separated. The experiment has recently been made of putting together 
zinc and copper filings and pressing them under a powerful hydraulic 
press, and producing a metal which had every characteristic of brass. 
The inference is also that the two metals once together, apparently 
alloyed, may be separated by pressure; and this can be done. The same 
has been done for other alloys and for other metals in a finely divided 
state; nor should we be astonished at this, for it has been known for a 
long time that platinum sponge may be compressed to metallic platinum, 
and the experiment of making solid pieces from either sheets or powder 
of the more fusible metals, especially lead, has been repeated a great 
many times. 

I have separated from many of these metals volumes of gas which 



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436 

were five, sometimas ten, times the bulk of the metal. At some future 
time I hope to analyze this gas, and ascertain exactly what it is. This 
phenomena of the separation of gas always occurs in those metals which 
have been most compressed, and it would appear as if the brittlenees 
was owing in a greskt many cases to the expansive force of the gas at high 
pressure, which is a force within the metal tending to help any force 
applied from without which would deteriorate it. 

I, therefore, cannot admit that there are any peculiarities in these 
metals which must undergo great pressure, which cannot be remedied. 
The cause in every case can be ascertained, and the defect remedied, 
if the proper means are used. I devised a machine for this purpose, 
but, unfortunately, the necessity which led to the examination of these 
metals ceased to exist befoi*e the machine could be built. 

I hope at some future time, in presenting to the Society the results of 
my study on the law of fatigue and refreshment of metals, to describe 
this machine, and I hope to show how it may be possible to ascertain, 
not only the defects in these metals, but the want of homogeneity as well 
as fatigue in metals which are used for structural purposes. 

O. E. MiGHAELis. —I have listened with great interest to the remarks 
of Dr. Egleston, and I sincerely trust that he will soon be able to pre- 
sent to us the results of his novel investigations, which will, no doubt, 
throw much light upon a hitherto i^nsolved problem. 

At the same time, I must say that the Doctor does not appear to ap- 
preciate the actual difficulty presented by the case under discussion. It 
is not sought to discover the cause of the failure of different batches of 
metal ; but why a certain metal stood the severest, the most searching 
tests successfully, and thereafter failed in the gun. The cartridge metal 
described underwent the various operations of drawing, heading and 
tapering, unannealed, and gave no sign of weakness ; its strain -diagrams 
are the counterparts of those given by accepted metal ; its behavior was 
satisfactory in the eprouvette ; yet it could not be used safely for the 
manufacture of cartridges. Of course, there must be a reason for this 
failure, but it was not discoverable under the mobt exhaustive tests that 
our experience led us to institute, and the presentation of this fact is the 
main object of the paper. 



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